giant parotid pleomorphic adenoma with atypical...
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Case ReportGiant Parotid Pleomorphic Adenoma with Atypical HistologicalPresentation and Long-Term Recurrence-Free Follow-Up afterSurgery: A Case Report and Review of the Literature
Mohammed AlKindi ,1 Sundar Ramalingam ,1 Lujain Abdulmajeed Hakeem ,1
and Manal A. AlSheddi 2
1Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh, Saudi Arabia2Department of Basic Sciences, College of Dentistry, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
Correspondence should be addressed to Sundar Ramalingam; [email protected]
Received 5 July 2020; Revised 14 August 2020; Accepted 21 August 2020; Published 1 September 2020
Academic Editor: Pravinkumar G. Patil
Copyright © 2020 Mohammed AlKindi et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.
Salivary gland tumors (SGT) comprise 3% of all head and neck tumors, are mostly benign, and arise frequently in the parotid gland.Pleomorphic adenoma (PA) is the commonest SGT, representing 60-70% of all benign parotid tumors. Clinically, parotid PApresents as irregular, lobulated, asymptomatic, slow-growing preauricular mass, involving both superficial and deep lobes, andcould grow to gigantic proportions. Histologically, PA has epithelial and mesenchymal elements in chondromyxoid matrix andis managed surgically. Based on a review of 43 cases reported in English literature since 1995, giant parotid PA is reported aslarge as 35 cm (diameter) and 7.3 kg (resected weight). Although rare, 10 cases of malignant transformation were reported in thereview. Surgical management included extracapsular dissection (ECD), superficial parotidectomy, and total parotidectomy forbenign tumors, and adjuvant radiation or chemotherapy for malignant tumors. We further present the case of a 36-year-oldhealthy male with slow-growing and asymptomatic giant parotid PA, of 4-year duration. The patient presented with firm,lobulated preauricular swelling, provisionally diagnosed as PA based on radiographic and cytological findings. The tumor wasresected through ECD, and the patient had uneventful postoperative recovery and a 7-year recurrence-free follow-up period.Histological examination revealed epimyoepithelial proliferation punctuated by chondromyxoid areas, with extensive squamousmetaplasia and keratin cysts. To the best of knowledge from indexed literature, giant parotid PA is rarely reported in SaudiArabia. In addition to its rarity, this case is reported for its benign nature despite atypical histological presentation, successfulsurgical management without complications, and long-term recurrence-free follow-up. Based on this report, clinicians must beaware of atypical histological presentations associated with PA and plan suitable surgical management and follow-up to avoidmorbidity. Nevertheless, attempts must be made to diagnose and manage these lesions at an early stage and before they reachgigantic proportions.
1. Introduction
Neoplastic lesions of the salivary glands are uncommon andcomprise less than 3% of all reported head and neck tumors[1, 2]. Nearly 80% of the reported salivary gland tumors(SGT) are benign and occur predominantly in major salivaryglands, with the parotid gland being the commonest site (70–80%) [2, 3]. Often presenting as slow-growing, painlessmasses, tumors involving major salivary glands are rarely
aggressive or malignant (<10%). On the contrary, tumors ofminor salivary glands while occurring rarely have a prepon-derance to be malignant (80–90%) [2, 3]. Pleomorphic ade-noma (PA) is the commonest SGT, accounting for almost60–80% of all benign SGT and 60–70% of all parotid glandtumors [1, 3]. Clinically, PA presents as an irregular, rubbery,lobulated, slow-growing mass without any associated pain ordiscomfort. The presenting complaint is typically related tounpleasant or unesthetic facial appearance, which when
HindawiCase Reports in DentistryVolume 2020, Article ID 8828775, 18 pageshttps://doi.org/10.1155/2020/8828775
disregarded can lead to patients reporting with huge lesions[4]. Reports in the literature suggest resected dimensions ofPA to be frequently in the range of 2 cm to 6 cm and rarelyreaching even up to 25–35 cm [4, 5].
As the name suggests, PA is histologically categorized as abenign mixed (pleomorphic) tumor of ductal and myoe-pithelial cell origin. Owing to the pluripotential nature ofmyoepithelial cells, the tumor is composed of epithelial andfibrous, myxoid, and cartilaginous mesenchymal elementssurrounded by a pseudocapsule, with occasional squamousmetaplasia [3, 4, 6]. While the diagnosis of PA is based pri-marily on clinical and histological findings, the mainstay ofmanagement is by surgical excision [1, 4]. Depending upontheir size and depth of involvement, parotid PA is surgicallymanaged either by superficial parotidectomy (SP), extracap-sular dissection (ECD), or total parotidectomy (TP). All ofthe above procedures carry the risk of postoperative facialnerve paralysis and Frey’s syndrome [1, 7]. Recurrence isusually associated with inadequate clearance and incompleteremoval of pseudocapsule, and malignant transformation hasbeen reported with large, long-standing PA [4, 7].
Although uncommon, giant pleomorphic adenomas ofthe parotid gland have been reported. An electronic searchof the English-language articles through the Medline, Scopus,and Google Scholar databases revealed 43 reports of giantparotid PA since 1995 [4, 8–32], with sizes ranging up to28-33 cm [15, 18, 27] and tumor mass ranging up to 6.85–7.3 kg [10, 27]. Major reasons for patients reporting withlarge PA are lack of resources, inaccessibility to medical facil-ities, fear of surgical procedure, and poor awareness, com-pounded by an asymptomatic and slow-growing lesion [4].The aim of this paper is to add to the existing scientific liter-ature, a case of giant parotid PA treated surgically by ECD,followed by uneventful postoperative recovery and a 7-yearrecurrence-free follow-up. This paper also attempts to high-light the benign nature of parotid PA, despite the atypicalhistological presentation, which could be associated with it.
2. Case Report
A 36-year-old healthy male patient reported to the oraland maxillofacial surgery outpatient clinic at the Collegeof Dentistry and Dental University Hospital, King SaudUniversity, in October 2012. The patient sought medicalattention for a slow-growing, painless swelling in the rightpreauricular region. History revealed that the patientnoticed the swelling almost 4 years ago, and since then,it had gradually increased in size with no obvious symp-toms or changes to the overlying skin. Upon interviewing,the patient reported no relevant medical or surgical historyand mentioned fear of surgery and absence of discomfortas reasons for delaying medical consultation, in spite ofan unesthetic facial appearance.
Clinical examination revealed a firm, nontender, nodular,and mobile swelling with apparently normal overlying skin.The swelling extended superoinferiorly from the level of theexternal ear to the lower border of the mandible and antero-posteriorly from the angle of the mouth to the posterior bor-der of the mandible. There was no lymph node involvement
or facial nerve deficit (Figure 1). Preoperative computedtomography (CT), magnetic resonance imaging (MRI), andfine-needle aspiration cytology (FNAC) were ordered. CTwith contrast revealed a well-defined mass lesion in thesuperficial lobe of the right parotid gland, without any under-lying bony erosion and normal-appearing pharynx, larynx,and parapharyngeal spaces. While confirming the CT find-ings, head and neckMRI further demonstrated a well-demar-cated, heterogeneous, mass lesion measuring 10 × 7 × 8 cm inmaximum dimension (Figure 2). FNAC showed numerousscattered groups and clusters of plasmacytoid myoepithelialcells, associated with a chondromyxoid matrix. A provisionaldiagnosis of PA with no malignant tendency was arrived atbased on CT, MRI, and FNAC findings.
Surgical removal of the right parotid SGT under generalanesthesia was planned and explained to the patient. Follow-ing informed consent, the lesion was excised completelythrough ECD, with preservation of all branches of the facialnerve. The right parotid gland was approached using a cervi-cally extended preauricular skin incision. A clearly discern-ible plane of dissection around the tumor was used fordissecting the tumor mass, without any iatrogenic damageto the facial nerve branches. Owing to the long-standingnature, multiple small feeder vessels had to be ligated circum-ferentially around the tumor to achieve hemostasis. Theintraoperative period was unremarkable, and the patientdid not require any blood transfusions (Figure 3). Theresected mass was bilobed and ovoid in shape with a finaldimension of 7 × 13 × 7 cm and weighing 1.2 kg.
Histopathological examination of the excised specimengave a gross appearance of a partially encapsulated mass con-taining myoepithelial and ductal proliferation. There wasmarked stromal hyalinization, squamous metaplasia, andkeratinization. Some epithelial islands exhibited papillaryconfiguration, along with large cysts and inflammation.Chondromyxoid changes and fibrosis were evident through-out the tumor. Certain foci of tumor islands were seenapproaching and breaking through it. Hematoxylin and eosin(H&E) stained sections revealed a partially encapsulatedtumor with variable histopathological features and focaleffacement of the fibrous capsule. The tumor typicallyshowed epithelial/myoepithelial proliferation punctuated bychondromyxoid areas. Aggregates of plasmacytoid myoe-pithelial cells as well as ducal differentiation surrounded byclear myoepithelial cells were evident. Based on the abovefindings, a final diagnosis of benign PA was reached. Whilethe tumor sections showed no evidence of malignant change,there was extensive squamous metaplasia and keratin cystformation, which were atypical for PA (Figure 4). The patientwas therefore advised close follow-up, once every month forthe first year postoperatively and subsequently once in sixmonths.
At 6 weeks postsurgery, the patient had unremarkablewound healing without any neurological deficit of the facialnerve (Figure 5). As of December 2019, the patient had arecurrence-free follow-up period of 7 years and presentedwith normal activity of muscles of facial expression, indicat-ing the absence of any long-term facial nerve weakness(Figure 6).
2 Case Reports in Dentistry
3. Discussion
The parotid gland is the largest salivary gland with an averageweight ranging from 0.015 to 0.021kg and measuring approx-imately 5:8 × 3:4 cm in the craniocaudal and ventrodorsaldimensions, respectively. Being the first salivary gland to
develop in utero, during the 6th gestational week, it is anatom-ically located bilaterally between the mastoid process oftemporal bone and ramus of the mandible. The terminalbranches of the facial nerve are an important anatomic land-mark which divide the parotid gland into its superficial anddeep lobes [33]. Although SGT are uncommon, they are
(a) (b)
Figure 1: Preoperative clinical photograph of the right preauricular swelling. (a) Right lateral facial view shows the swelling extendingsuperoinferiorly from a point anterior to the helix of the external ear until the lower border of the mandible; anteroposteriorly, theswelling is seen extending from the angle of the mouth to the posterior border of the mandible; the ear lobe is deflected outward andelevated, and the skin overlying the swelling appears free of any ulceration, puckering, or discharge. (b) Frontal facial view shows theswelling causing facial asymmetry and obliterating the view of most of the right external ear; there is no clinical evidence of facial nerveweakness or deficit.
R
(a)
R
(b)
Figure 2: Preoperative radiographic examination of the right preauricular swelling. (a) Contrast-enhanced computed tomography axialsection at the level of mandibular teeth shows a well-defined mass lesion in the superficial lobe of the right parotid gland, without anyunderlying bony erosion and normal-appearing pharynx, larynx, and parapharyngeal spaces. (b) Magnetic resonance imaging coronalsection along the posterior border of the mandible shows a large, heterogeneous, well-demarcated solid mass lesion within the rightparotid superficial lobe and measuring 10 × 7 × 8 cm at maximum dimensions.
3Case Reports in Dentistry
predominantly benign and are reported frequently in theparotid gland [2]. The present report details a case of giantPA in the right parotid gland, along with its surgical manage-ment, histological presentation, and long-term recurrence-freefollow-up.
Pleomorphic adenoma is the commonest mixed SGTarising in the parotid gland, and several cases have beenreported in the literature. Although there are no specificphysical criteria outlined in the literature to classify giantparotid PA, the earliest recorded case report dates back to1863 [27]. In this report, Spence reported a mixed tumorinvolving lateral face and neck and a resected mass weighinggreater than 1 kg [27]. Similarly, Short and Pullar (1956)reviewed and reported a case of giant parotid PA weighingabout 2.3 kg [27]. In a report reviewing 31 cases of giantparotid PA over a period of 140 years by Schultz-Coulon,the resected tumor weights ranged from 1.0 to 26.50 kg, witha greater female predilection (64.5%) and only 3 cases ofmalignant transformation [15]. Based on a review of the 10
largest parotid PA published between 1863 and 1994, Buent-ing et al. reported resected tumors ranging in weight from2.83 to 26.50 kg, in patients with age ranging from 25 to 85years and 90% female predilection [10].
A literature search was conducted to review giant parotidPA cases reported in Medline, Scopus, and Google Scholardatabases. The search strategy involved a combination ofsearch keywords including “GIANT”, “PAROTID GLAND”,and “PLEOMORPHIC ADENOMA”, based on which 288articles were identified from the three databases (Med-line—66; Scopus—63; Google Scholar—159). Reviewingtheir abstracts, articles published in English only wereselected based on them reporting a case or series of cases ofgiant parotid PA, including clinical, radiographic, histologi-cal, and surgical outcomes. Twenty-six articles published inEnglish language were identified [4, 8–32] since 1995, andthey reported 43 cases of PA in total. While most of the arti-cles selected for review were single case reports, three articleswere case series reporting about two cases [16], three cases
(a) (b)
Figure 3: Intraoperative photograph showing (a) the surgical plane for extracapsular dissection of the right parotid tumor and (b) the excisedtumor specimen.
500 𝜇m
(a)
200 𝜇m
(b)
Figure 4: Histological examination of the excised tumor specimen showing (a) a partially encapsulated mass lesion containing myoepithelialand ductal proliferation, with stromal hyalinization, squamous metaplasia, and keratinization; epithelial islands exhibiting papillaryconfiguration, large cysts surrounded by inflammation, focal areas of chondromyxoid changes and fibrosis, and tumor islandsapproaching and penetrating the capsule are evident (HE original magnification ×4); (b) extensive squamous metaplasia and keratin cystformation are conspicuous at higher magnification (HE original magnification ×10).
4 Case Reports in Dentistry
[17], and 15 cases [32], respectively. The largest case series inthe present review, comprising 15 PA patients, was reportedby Pareek et al. [32].
Although majority of the reported cases were in patientsaged 45 years or older (n = 30, 69.8%), the age at clinical pre-sentation and surgery ranged from 21 to 92 years. Theasymptomatic, slow-growing nature of pleomorphic ade-noma was evidenced by the fact that the duration from thefirst observation of lesion to reporting for treatment variedfrom 5 to 35 years. Demographically, there were morefemales (n = 25, 58.1%) than males, and all reported caseswere unilateral, with the right side (n = 23, 53.5%) affectedmore than the left. In terms of clinical dimension, the tumorsranged from 3 to 5 cm in diameter [16, 17], until 35 × 28 cm[27], in two perpendicular planes. The clinical dimensionscorroborated with the resected tumor weight, wherein thesmallest tumor weighed 0.12 kg [16] and the largest weighed7.3 kg [27]. Predominant clinical presentation of the tumorswas that of a large, lobulated, and pedunculated mass withapparently normal overlying skin. Ulceration of the skinwas reported in eight patients, out of which five were report-edly associated with malignant change [15, 23, 24, 30, 32],and the remaining three were due to injury [18, 29, 32]. Ana-tomically, the tumor more commonly involved the superfi-cial lobe of the parotid gland (n = 29, 70.7%) giving rise tothe clinical presentation of a large preauricular mass. Never-theless, when the deep lobe of parotid and parapharyngealspaces were involved by the tumor, patients presented withan intraoral swelling leading to soft palate displacement, dif-ficulty in swallowing and breathing, and obstructive sleepapnea [11, 13, 16, 17, 22, 25]. While diagnosis was primarilybased on clinical and radiographic (USG, CT, andMRI) find-ings, preoperative diagnosis was established through FNAC
in most cases. The clinical, radiographic, surgical, and histo-logical findings in the reviewed case reports are detailed inTable 1.
Preoperative diagnosis of PA is routinely based on clini-cal findings, supplemented by radiological investigationssuch as CT, MRI, and USG [2]. The role of FNAC in arrivingat a provisional diagnosis has been debated and considerednonrepresentative due to varying histological patterns at dif-ferent sites within the same tumor [34]. In terms of histo-pathological diagnosis, the characteristic feature of PA is itshistological diversity and differing arrangements of epithelialand mesenchymal tissue elements. Das and Anim [34], basedon a study comparing FNAC and histological sections in PA,reported consistent findings of epithelial cells in a myxoidstroma through cytological and histological examination.Nevertheless, they reported better characterization of onco-cytic changes such as acini, giant cell and mucus globule for-mation, and squamous and chondroid metaplasia inhistological sections [34]. Preoperative diagnosis of PA inthe present case was based on a combination of clinicalexamination, radiographic investigations, and FNAC. Ourradiographic finding (CT and MRI) of well-demarcated, lob-ulated, and heterogeneous mass lesion involving the parotidgland and FNAC finding of plasmacytoid epithelial cells ina chondromyxoid matrix were in coherence with the major-ity of cases reported in the review (Table 1). Additionally,necrotic changes [10, 24, 30] and calcifications [4, 30], withinthe tumor, have also been reported in the literature, based onCT and in association with malignant change [24, 30]. Thecombination of CT and MRI enables optimum preoperativediagnosis of pleomorphic adenomas and precise planningof the surgical approach for tumor resection [11]. In additionto volumetric information, CT with contrast provides
(a) (b)
Figure 5: Postoperative clinical photograph taken 6 weeks postsurgery. (a) Lateral facial view shows healing surgical incision without anyobvious postoperative sequelae. (b) Symmetric facial appearance observed in the frontal facial view, with no clinical weakness of musclesof facial expression.
5Case Reports in Dentistry
knowledge about vascularity of the tumor andMRI shows therelationship of the tumor to surrounding vital structures inthe head and neck regions [11].
The treatment of PA irrespective of their size, severity, ormalignant potential is only by surgery. Based on our litera-
ture review, giant PA involving the superficial lobe of parotidwas managed either by SP or ECD [4, 10, 24, 26–29, 31, 32].On the contrary, TP was reportedly done for tumors exhibit-ing malignant characteristics [8, 12, 15, 17, 19, 20, 23, 30] andthose involving both the deep and superficial lobes [9, 13, 14,
(a) (b)
(c) (d)
(e)
Figure 6: Postoperative clinical photograph taken 7 years postsurgery with facial gestures eliciting unrestrained action of different muscles offacial expression. (a) Unremarkable healing of the surgical wound without any scarring and the patient is seen smiling. (b) Frontal facial viewshowing symmetric appearance and the patient is seen puffing the cheeks. (c, d) Bilateral symmetric eyelid closure and opening. (e) Thepatient is seen grinning broadly.
6 Case Reports in Dentistry
Table1:Reviewof
giantparotidpleomorph
icadenom
acase
repo
rtsandtheirdemograph
ic,clin
ical,radiographic,surgical,and
histologicalfind
ings.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Alvarez-C
añas
andRod
illa
(1996)
[8]
86/F
15years
Left
Largepainless
preauricular
mass
which
enlarged
sudd
enlyover
the
past1year
and
associated
with
facialnervedeficit
Onlyclinical
exam
ination
Totalparotidectom
y9:5
×8×
7cm
Sudd
enincrease
insize
with
facialnerve
deficit
Mixed
malignant
transformationof
PAwithsalivary
ductalcarcinom
aandhigh-grade
fibrosarcomaelem
ents
Patient
developedlocal
recurrence
oftumor
anddied
6mon
thsafter
surgery
Lomeo
(1996)
[9]
74/F
35years
Left
Largepreauricular
mass
Onlyclinical
exam
ination
Totalparotidectom
y
Patient
was
convincedfor
surgeryby
grandchildren
Pleom
orph
icadenom
a
Buentingetal.
(1998)
[10]
85/F
20years
Right
Large,multino
dular
preauricular
mass
withevidence
ofinfection.
The
mass
was
tenselycystic
andhadprom
inent
veinsnear
thebase
CTshow
eda
parotidmass14
cmacross
with
extensivenecrotic
fociandnu
merou
sfeedingvessels,
which
wereno
tam
enableto
embo
lization
Extracapsular
dissection
ofthe
tumor
mass
26cm
diam
eter
(6.85kg)
Inadvertent
injury
tothe
base
ofthemass
resulting
inbleeding
and
infection
Pleom
orph
icadenom
awithextensive
necrosisand
cartilagino
usmetaplasia
1-year
recurrence-free
follow-up
Rod
riguez-
Ciurana
etal.
(2000)
[11]
48/F
30years
Right
Largemassin
the
subm
andibu
larand
laterocervical
region
s,extend
ing
intraorally
from
soft-palateto
floo
rof
mou
th
MRIshow
edamass
involvingthedeep
lobe
oftheparotid
gland,
extend
ing
into
paraph
aryngeal,
prestyloid,and
subm
andibu
lar
spaces,d
isplacing
externaland
internalcarotid
arteries
and
thinning
theramus
ofmandible.
Measuring
6×5×
4cm
.FNACwas
indicative
ofPA
Deeplobe
parotidectom
ythroughcervical
transparotid
approach
Pleom
orph
icadenom
a
Transient
facial
nerveweakn
ess
for4weeks
Manuel(2002)
[12]
68/F
Left
Recurrent
parotid
masswhich
was
incompletely
excisedearlierand
diagno
sedas
mixed
malignant
tumor
Total
parotidectom
y,with
removalof
facial
nervebranches
due
totumor
infiltration
andmod
ified
neck
dissection
Recurrent
lesion
inthepreviously
excisedtumor
site
Carcino
sarcom
aarising
from
PA,w
ithresidu
alPA,epimyoepithelial
carcinom
a,and
pleomorph
icsarcom
a.Multiplemetastatic
cervicallymph
nodes
Patient
was
operated
for
metastatic
anterior
chest
wallm
ass,7
mon
ths
postsurgeryand
hadan
18-
mon
thdisease-
free
follow-up
7Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Panou
ssop
oulos
etal.(2002)[13]
63/M
30years
Left
13×12
cm
Large,lobu
lated
massin
the
subm
andibu
lar,
preauricular,and
laterocervical
region
s,extend
ing
intraorally
tothe
lateralp
haryngeal
wallatthelevel
oftongue
MRIshow
edawell-
definedmass
involvingbo
thsuperficialanddeep
lobesof
theparotid
gland,
and
extend
inginto
the
paraph
aryngeal
space,displacing
tissuesdeep
tothetonsil
Totalparotidectom
ythroughcervical
transparotid
approach
Pleom
orph
icadenom
a
deSilvaetal.
(2004)
[14]
76/M
>30years
Left
20×30
cm
Large,oval
preauricular
swellin
g,firm
inconsistency,
withveno
usengorgem
enton
overlyingskin
andmovable
FNACwas
indicative
ofPA
Totalparotidectom
ywithpreservation
offacialnerve
20×14
×12
cm(3.5kg)
Pleom
orph
icadenom
a
Facialnerve
deficitobserved
1week
postop
eratively
andrecovered
90%
by1mon
th
1-year
recurrence-free
follow-upand
complete
recovery
offacialnerve
function
Hon
daetal.
(2005)
[15]
72/F
20years
Left
Large,pedu
nculated
preauricular
mass
extend
ingup
tothe
subm
andibu
lar
region
,witha
historyof
rapid
grow
thin
preceding
3mon
thsand2
areasof
ulceration
withyellowish,
foul-
smellin
gdischarge
inthelower
partof
themass.An
associated
anterior
chestwallm
ass
measuring
10×8
cmwas
clinically
identified
CTshow
edamass
withmultiple
encapsulated
nodu
lesinvolving
theentire
parotid
gland,
having
severalfeeder
vesselsandsupp
lied
predom
inantly
bythetransverse
facial
artery.C
oincidental
find
ingof
abno
rmal
skullb
aselesion
measuring
4cm
indiam
eter.C
hest
radiograph
revealed
multiplemetastatic
nodu
les,measuring
arou
nd1cm
,in
both
lungs
Totalparotidectom
y+simultaneou
sresectionof
anterior
chestwallm
ass
33×18
×17:5cm
exop
hytictumor
(6.051
kg)
Sudd
enincrease
insize
with
ulceration
and
discharge
Pleom
orph
icadenom
awithfocalareas
ofmalignant
adenocarcino
macells
withhyperchrom
atic
nucleiandincreased
mitoticfigures.Similar
histologicalfind
ings
observed
intheresected
anterior
chestwallm
ass
Patient
died
6mon
ths
postsurgery,
dueto
metastaticlung
disease
8 Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Ruiz-Laza
etal.
(2006)
[16]
54/M
5years
Left
3cm
Solid
massin
preauricular
and
mandibu
larangle
region
s
MRIshow
eda
multilobu
latedmass
measuring
8cm
indiam
eter
and
extend
ingfrom
deep
lobe
ofthe
parotidglandinto
paraph
aryngeal
space,displacing
the
pharyngealairw
aymedially
andthe
jugularandcarotid
vesselspo
steriorly.
FNACwas
indicative
ofPA
Totalparotidectom
ythroughcervical
transparotid
approach
and
facialnerve
preservation
Pleom
orph
icadenom
a
Postoperative
facialnerve
deficitwhich
recovered
completelyin
6mon
ths
3-year
recurrence-free
follow-up
Ruiz-Laza
etal.
(2006)
[16]
21/M
Right
Intraoralm
ass
occupyingtheentire
softpalatewithno
otherassociated
symptom
s
MRIshow
edawell-
definedmasslesion
measuring
6×5×
4cm
inthe
paraph
aryngeal
spaceandwith
apparent
continuity
tothedeep
lobe
oftheparotidgland.
FNACwas
indicative
ofPA
Surgicalexcision
oftumor
masson
ly,
throughintraoral
approach
and
“Dou
ble-Y”incision
insoftpalate
11×10
cm(0.12kg)
Pleom
orph
icadenom
a
3-year
recurrence-free
follow-up
Sergi etal.
(2008)
[17]
36/M
1year
Left
5cm
Solid
preauricular
mass
USG
show
edtwo
hypo
echo
genic,
lobu
latedmasses
measuring
2:5×1:9
×1:6
cminthedeep
lobe
oftheparotid
glandand4:4×
5:1×4:6c
mpo
sterior
tomandibu
lar
ramus.M
RI
revealed
expansive
massmeasuring
abou
t5cm
inthe
deep
lobe
ofthe
parotidgland,
extend
ingfrom
mandibu
larangleto
lateralp
haryngeal
wallm
edially
Using
cervical
transparotid
approach,
superficialanddeep
lobe
parotidectom
yperformed
separatelyto
preserve
facial
nervebranches
Pleom
orph
icadenom
a
Transient
neurological
deficitof
marginal
mandibu
lar
branch
offacialnerve
9Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Sergietal.
(2008)
[17]
42/M
Right
3cm
Solid
preauricular
mass
MRIshow
edamass
inthedeep
lobe
oftheparotidgland,
extend
inginto
paraph
aryngeal
spaceanddisplacing
theph
aryngeal
muscles
medially.
FNACwas
indicative
ofPA
Using
cervical
transparotid
approach,
superficialanddeep
lobe
parotidectom
yperformed
separatelyto
preserve
facialnerve
branches
Increasedin
size
over
2mon
ths
Pleom
orph
icadenom
a
Sergietal.
(2008)
[17]
38/F
Left
Noextraoral
swellin
g.Intraoral
masslateraltothe
softpalateand
displacing
itacross
themidlin
e
MRIshow
edinho
mogeneous,
expansivemass
arisingfrom
the
deep
lobe
ofthe
parotidglandand
measuring
5:5×5:5
cmin
thelateral
pharyngealspace.
The
masswas
seen
displacing
the
pterygoidand
pharyngealmuscles
medially.FNACwas
indicative
ofPA
Separatesuperficial
anddeep
lobe
parotidectom
ythrough
transcervical,
mandibu
larsplit
approach
topreserve
facialnerve
branches
Painwhile
swallowingand
sensationof
foreignbody
inthethroat
since
5mon
ths
Pleom
orph
icadenom
awithanu
cleusof
carcinom
aex-PA
Postoperative
radiotherapy
Takaham
aetal.
(2008)
[18]
78/M
>30years
Right
30cm
Large,multino
dular
preauricular
mass
extend
ingto
the
subm
andibu
lar
region
andcrossing
themidlin
e.Fo
cal
areasof
ulceration
inthelower
partof
themass
Onlyclinical
exam
ination
Totalparotidectom
y28
×20
×16
cm(4.0kg)
Pleom
orph
icadenom
a
Bhu
tta(2009)
[19]
63/F
Left
Slow
-growingmass
intheleftsuperficial
parotid
Onlyclinical
exam
ination
Excisiondo
nein
1993,followed
bymultiplerecurrences
managed
surgically
throughexcision
from
1995-2006
Earlylesion
was
suggestive
ofPA.
Recurrent
lesion
sresembled
PAwith
high
mitoticrate
andno
malignancy
45Gyexternal
beam
radiation
therapy(in25
fraction
s)given
in2000
toprevent
recurrence
In2006,C
Tshow
edaright
kidn
eymass,
diagno
sedas
metastasizing
PAby
histology
(typicalfeatures
ofPAwith
positive
Ki67
staining)
10 Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Karpo
wiczetal.
(2010)
[20]
45/M
Right
Subcutaneous
parotidmasswith
ipsilateralcervical
lymph
adenop
athy
involvingmultiple
nodes.Associated
withseverepain
and
rapidincrease
insize.C
linically
staged
asstageIva
malignant
disease
Onlyclinical
exam
ination
Totalparotidectom
ywithcomprehensive
neck
dissection
Non
encapsulated
tumor
measuring
abou
t3.5cm
Severe
pain
and
rapidincrease
insize
Malignant
epithelial
cells
ina
chon
drom
yxoidstroma
indicative
ofcarcinom
aex-PA.M
alignant
foci
includ
edhigh-grade
squamou
scell
carcinom
aand
adenocarcino
ma.One
ofthecervicallymph
nodesshow
edevidence
ofmetastaticcarcinom
a.Im
mun
ohistochem
istry
identified
amelanom
acompo
nent
Twomon
ths
postsurgery,the
patientrepo
rted
severe
pelvic
pain,d
iagnosed
asmetastatic
bone
disease
throughMRI
Patient
died
3mon
ths
postsurgerydu
eto
metastatic
disease
Cetin
etal.
(2012)
[21]
55/F
20years
Left
15×15
×20
cm
Largepreauricular
massextend
ingto
cervicalregion
s,withoverlyingskin
atroph
icand
vascular
USG
show
eda
lobu
latedmassin
theparotidgland
withbo
thho
mogeneous
and
heterogeneou
secho
textures
Totalparotidectom
yPleom
orph
icadenom
a
Morariu
etal.
(2012)
[22]
42/M
Right
Largemassarising
from
thelateral
pharyngealwall,
displacing
thesoft
palateanduvula,
andnarrow
ingthe
pharyngealairw
ay.
Associated
symptom
sof
painfulswallowing,
heavysnoring,and
sleepapneaforpast
1year
MRIshow
eda
circum
scribedmass
lesion
7×6×
4cm
extend
ingfrom
the
deep
lobe
ofthe
parotidglandinto
theparaph
aryngeal
spacewithfluid
spaces
and
septation.
CT
angiogram
while
show
ingsplayed
internaland
externalcarotid
arteries,ruled
out
anyabno
rmal
vascularity.
TransoralFN
AC
was
indicative
ofPA
Deeplobe
parotidectom
ythrough
transparotid
approach
Pharyngod
ynia
andno
cturnal
hypo
xia
symptom
s
Pleom
orph
icadenom
a
Patient
repo
rted
relieffrom
nocturnal
hypo
xia,
snoring,and
sleepapnea
symptom
s,po
stop
eratively
6-mon
threcurrence-free
follow-up
11Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Yoshida
etal.
(2013)
[23]
40/F
17years
Left
Smallp
arotid
swellin
gbefore
17years,diagno
sedas
PAby
FNAC.
Surgerydelayedfor
10yearsdu
eto
patient’s
fear
and
then
lostto
follow-
up.Swellin
ggrew
rapidlyin
past6
mon
ths,causing
gaitdisturbanceand
skin
ulceration
with
foul-smellin
g,bloo
dydischarge
from
thelower
partof
lesion
CTshow
eda
nodu
larmass
arisingfrom
the
parotidglandand
attached
inits
deeper
aspectto
the
carotidsheath.
Evidenceof
metastasisin
chest
radiograph
owingto
bilateralh
ilar
lymph
adenop
athy
andcoin-shaped
radiolucency
inthe
rightlung.Incision
biop
sywas
indicative
ofPA,
withclinical
suspicionof
malignancy
Totalparotidectom
yanden
bloc
resectionof
the
tumor
alon
gwith
thelower
portionof
theauricle
25×28
×18
cm(4.80kg)
Rapid
grow
thof
tumor
inlast6
mon
thswith
cervicaland
thoracic
scoliosisand
gaitdisturbance
Nearly80%
ofthe
resected
tumor
sections
show
edevidence
ofPA.
Sections
ofthetumor
near
theulceratedareas
show
edun
differentiated
malignant
cells
indicative
ofcarcinom
aex-PA
Postoperative
adjuvant
chem
otherapy
formetastasis
6-mon
thfollow-upwith
nolocal
recurrence
Pam
uketal.
(2014)
[24]
82/F
20years
Right
13×13
×10
cm
Large,multilobu
lar
preauricular
mass
withareasof
ulceration
and
necrosison
overlyingskin
CTshow
edagiant,
exop
hyticmassin
thesuperficiallobe
oftheparotidgland
withmultiple
necroticspaces
and
enhanced
vascularity.
Incision
albiop
sywas
indicative
ofa
salivarygland
neop
lasm
witho
utrulin
gou
tmalignant
transformation
Superficial
parotidectom
ywith
excision
ofoverlying
ulceratedskin
14×12
×9c
m
Pleom
orph
icadenom
awithmultiplefociof
neop
lasticproliferation
,alon
gwithcellu
lar
atypiaandnecrosis.
Finald
iagnosis
carcinom
aex-PA
Postoperative
radiotherapy
60Gy
Patient
died
8mon
ths
postsurgery
dueto
cerebrovascular
accident
Datarkarand
Deshp
ande
(2014)
[25]
40/F
Right
Large,firm
intraoral
massarisingfrom
thelateral
pharyngealwall,
displacing
thesoft
palateandcrossing
midlin
e.Associated
symptom
sof
difficulty
insw
allowingand
breathing,andsleep
apneaforpast6
mon
ths
CTshow
edparaph
aryngeal
spacemass
extend
ingmedially
across
themidlin
eandlaterally
betweenthe
posteriorbo
rder
oframus
andstyloid
process.MRI
show
edlobu
lated,
homogeneous
mass
lesion
extend
ing
Deeplobe
parotidectom
ythrough
transcervical,
mandibu
larsplit
osteotom
yapproach
5:5×
6:5×3:5c
m
Diffi
culty
insw
allowingand
breathing,and
sleepapnea
Pleom
orph
icadenom
a
Patient
repo
rted
relief from
sleep
apnea
symptom
s,po
stop
eratively
12 Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
from
thedeep
lobe
oftheparotidgland
withhypo
intense
septae
and
measuring
5:4×6:5
×3:5c
m,and
indentingon
lateral
pharyngealwall.No
involvem
entof
skull
base
orintracranial
extensionwas
observed.T
ransoral
FNACwas
indicative
ofPA
Sajid
etal.
(2015)
[26]
47/M
>7years
Right
26×20
cm
Large,no
dular
preauricular
mass
extend
ingup
tosubm
andibu
lar
region
inferiorly
andanteriorlyup
to2cm
posteriorto
thenasolabialfold
MRIshow
eda
heterogeneou
s,lobu
latedmassin
thesuperficiallobe
oftheparotidgland,
extend
ingmedially
upto
sterno
mastoid
andcarotidsheath.
FNACwas
indicative
ofPA
Superficial
parotidectom
ywith
excision
ofredu
ndantskin
22×24
×12
cm(1.8kg)
Pleom
orph
icadenom
a
Tarsitano
etal.
(2015)
[27]
83/M
>30years
Left
35×28
cm
Giant,
multino
dular,
pedu
nculated
mass
inthepreauricular
region
,extending
upto
thecervical
region
MRIsho
wed
agiant,
heterogeneou
smass
arisingfrom
the
superficiallobe
oftheparotidgland,
withwell-
demarcated
boun
daries
and
preservation
ofsurrou
ndingtissue
planes.C
Trevealed
prim
arybloo
dsupp
lythou
ghfacial
artery
and
numerou
ssm
all
feeder
vessels.
Incision
albiop
syconfi
rmed
the
diagno
sisof
PA
Extracapsular
dissection
ofthe
tumor
mass
33×27
×16
cm(7.3kg)
The
mass
becametoobig
andahind
rance
forthepatientto
ambu
late
Pleom
orph
icadenom
a
5-year
recurrence-free
follow-up
13Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
Akintub
ubo
etal.(2016)[4]
60/M
>10years
Left
25×23
×17
cm
Giant,lob
ulated,
andpedu
nculated
massin
the
preauricular
region
,extend
ingup
tocervicalregion
,with
firm
consistency
andmeasuring
almostthesize
ofthepatient’s
head
CTshow
edalarge
softtissue
mass
arisingfrom
the
superficiallobe
oftheparotidgland
andpresenting
with
severalamorph
ous
calcification
s,bu
twitho
utanybo
nyinvolvem
ent.FN
AC
was
indicative
ofPA
Superficial
parotidectom
y(5.5kg)
Patient
had
delayedsurgery
dueto
financial
constraints
Pleom
orph
icadenom
awith
multiplefociof
microcalcification
s
Reactionary
hemorrhagein
theim
mediate
postop
erative
period
,managed
through
exploratory
ligation.
Transient
neurological
deficitof
the
buccalbranch
offacialnerve
6-mon
threcurrence-free
follow-up
Calvo-
Henriqu
ezetal.
(2016)
[28]
72/F
14years
Right
20×15
cm
Giant
preauricular
mass,fixedto
underlying
tissues
andassociated
with
facialnervedeficit
(Hou
se-Brackman
Grade
III)
CTshow
edawell-
definedparotid
masswithmixed
solid
andcystic
areas.The
mass
extend
edsuperiorly
upto
tempo
ral
muscleand
cervicallyup
tothe
hyoidbo
ne.F
NAC
was
indicative
ofmixed
tumor
ofsalivaryglandorigin
Extracapsular
dissection
oftumor
massalon
gwitha
superficialskin
island
(1.6kg)
Facialnerve
deficit(H
ouse-
Brackman
Grade
III)
persisted
postop
eratively
Swain(2016)
[29]
92/M
>25years
Right
20×15
cm
Large,multino
dular
preauricular
mass
withskin
ulceration
dueto
repeated
traumaforpast6
mon
ths
CTshow
edawell-
definedmass
involvingthe
superficiallobe
oftheparotidgland.
FNACwas
indicative
ofPA
Superficial
parotidectom
ywith
preservation
offacialnerve
branches
Skin
ulceration
dueto
repeated
traumaforpast
6mon
ths
Pleom
orph
icadenom
a
Chaoetal.
(2017)
[30]
83/F
>20years
Right
Patient
presented
withaslow
-grow
ing,
preauricular
mass1
year
agowhich
was
provisionally
identified
asPA
throughFN
AC.
Patient
however
delayedsurgerydu
eto
person
alreason
s.Rapidly
proliferating
CTshow
eda
heterogeneou
sparotidmass
measuring
9×8:4
cmwithfociof
necrosisand
calcification
.The
masswas
inclose
proxim
ityto
inferior
aspectof
externalauditory
canaland
was
invading
Enbloc
resection
withtotal
parotidectom
y.Facialnerve
branches
except
the
buccalbranch
were
preserved.
The
buccalbranch
was
encasedin
tumor.
Selectiveneck
dissection
(levels
I-III)alon
gwith
resectionof
10.5cm
diam
eter
Rapid
grow
thwithskin
ulceration
inthe
last1year
Truemalignant
mixed
tumor
with
extensivefoci
ofnecrosisandpo
orly
differentiated
adenocarcino
ma
andchon
drosarcoma
compo
nents.No
histologicalevidence
oforiginalPAseen
Postoperative
radiotherapy
60Gy
At3-year
follow-up,
noloco
region
alrecurrence
was
observed.
Patient
however
presentedwith
lung
andliver
nodu
leson
PET
scan
14 Case Reports in Dentistry
Table1:Con
tinu
ed.
Autho
r(year)
Patient
demograph
ics
Preop
erativeevaluation
Surgicalintervention
Postoperative
period
Age
(in
years)/gender
Duration
oflesion
Affected
side
Clin
ical
dimension
Clin
ical
presentation
Investigations
Procedu
reResected
dimension
Reasonfor
surgery
Histologicalfi
ndings
Postoperative
course
Follow-up
exop
hytic,firm
,multilobu
lated
grow
thwithskin
ulceration
and
bleeding
wereseen
inthesamelesion
inthelast1year.Facial
nervefunction
was
intact
sterno
mastoid
and
massetermuscles.
Superficiallyskin
erosionwas
seen.
Noevidence
oflymph
node
orbo
nyinvolvem
ent.FN
AC
was
suggestive
ofcarcinom
aex-PA
infratem
poraland
paraph
aryngeal
spaces.Soft-tissue
reconstruction
with
anterolateralthigh
free
flap
Alnofaieetal.
(2020)
[31]
25/F
10years
Right
25×25
×15
cm
Irregular,
multilobu
lated,
giantmasswitha
sessile
base
inthe
rightparotidregion
extend
ingto
the
neck.O
verlying
skin
appeared
erythematou
swith
prom
inent
vasculatureandno
discharge.Sw
ellin
gwas
fixedto
underlying
tissues
andfacialnerve
function
was
unaffected
CTshow
eda
heterogeneou
smass
lesion
arisingfrom
theparotid.
MRI
show
edalobu
lated
heterogeneou
smass
withmultilocular
cysticchangesand
measuring
12×10
×12
cm.N
oextensionto
retrom
andibu
laror
paraph
aryngeal
spaces.F
NACwas
suggestive
ofPA
Superficial
parotidectom
ywith
preservation
offacialnerve
branches
18×17
×11:5cm
(1.5kg)
Patient
was
mentally
challenged
and
patient’s
mother
requ
ested
surgeryas
the
masshad
becometoo
largeand
hind
ered
daily
activities
Pleom
orph
icadenom
a
1-year
recurrence-free
follow-up
Pareeketal.
(2020)
[32]
(caseseries
comprising15
giantparotid
PA)
30-81years
(mean—
50.3)/5
males
and10
females
5-20
years
Right—9;
left—6
Alllesion
swere
greaterthan
10cm
indiam
eter
(range
10-
25cm
)
Majorityof
the
lesion
spresentedas
irregularor
ovoid
parotidmasseswith
well-defined
margins
and
overlyingskin
was
ulceratedin
2cases.
Non
eof
thecases
hadpreoperative
facialnerve
weakn
ess
Acombination
ofUSG
,CT,M
RI,and
FNACto
arrive
ata
provisional
diagno
sisof
PA.
One
case
was
preoperatively
diagno
sedwith
malignant
change
basedon
FNAC
Total
parotidectom
y—10;
totalp
arotidectomy
+neck
dissection
—1;
superficial
parotidectom
y—3;
enucleation—1.
Facialnerve
preservedinallcases
(2.0-3.5kg;
mean—
2.7)
Majorityof
the
patientsdelayed
surgerydu
eto
poor
awarenessand
underprivileged
socioecono
mic
status
Allcaseswere
histologicallyconfi
rmed
asPA,excepton
ecase
which
show
eda
malignant
change
Transient
facial
nervedeficitin
2patientswhich
recovered
within6
mon
ths.
Postoperative
radiotherapy
onlyforthe
malignant
case
Minim
um6-mon
threcurrence-free
follow-up
M:m
ale/F:female;CT:com
putedtomograph
y;MRI:magneticresonanceim
aging;FN
AC:fine-needleaspiration
cytology;P
A:pleom
orph
icadenom
a;USG
:ultrason
ograph
y;PET:positronem
ission
tomograph
y.
15Case Reports in Dentistry
16–18, 21, 32] (Table 1). Since the present case was that of aPA involving superficial parotid only (Figures 1 and 2), thepatient was surgically managed through ECD (Figure 3),avoiding any iatrogenic damage to the facial nerve(Figure 5). The surgical techniques for resecting PA haveevolved over the last century and have essentially focusedon preserving anatomic and functional integrity of the facialnerve and its branches [1, 7]. While intracapsular removalwas advocated, during the late 19th and early 20th centuriesin an attempt to avoid facial nerve injury, the techniquewas abandoned due to its high risk of recurrence (≥45%)[1, 7]. This leads to the popularity of SP, associated with avery low recurrence rate (≤2%), but still carrying a risk offacial nerve injury, Frey syndrome, and loss of facial contour[1]. In the last 2-3 decades, ECD has gained significance as asurgical technique which involves tumor resection along withthe capsule and a thin rim of extracapsular normal tissue,without attempting to identify or dissect the facial nerveand its branches [1]. Based on literature reviews, Kato et al.[1] and Bonavolontà et al. [7] reported that ECD is safe, iseconomical, and reduces operating time and risk of morbid-ity. They further considered it as the treatment of choice formobile, benign tumors involving the superficial lobe of theparotid gland [1, 7]. Moreover, traction due to gravity ingiant PA causes the tumor mass to descend away from thefacial nerve and its branches, thereby facilitating ease of dis-section, as encountered in the present case [10].
Several surgical approaches to remove PA and otherbenign parotid gland tumors involving the deep lobe andextending to the lateral pharyngeal and parapharyngealspaces have been reported [11]. These include cervical, cervi-cal-transpharyngeal, infratemporal fossa, parotid-cervical,transoral, and transparotid approaches. In the presentreview, 9 cases of PA were reportedly involving the deep lobeof parotid and extending into pharyngeal spaces. Thecervical-transparotid surgical approach was used for resec-tion in 6 cases [11, 13, 16, 17, 22], a transcervical, split-mandibulotomy approach was used in 2 cases [17, 25], andone case was managed through a transoral approach using“Double-Y” incision in soft palate [16] (Table 1). Postopera-tive complications following surgical resection of parotid PAare similar to that of other benign SGT [1, 4, 7, 23]. Theseinclude hemorrhage, hematoma, seroma, fistula, hypoesthe-sia, scarring, Frey syndrome, transient facial nerve injury,and facial paralysis [7]. While these complications are report-edly associated with all surgical techniques mentionedbefore, ECD was associated with a significantly lower riskof hypoesthesia, Frey syndrome, and facial nerve injury andparalysis [7]. Nevertheless, when dealing with large parotidtumors with suspected malignancy, which mandate identifi-cation and dissection of facial nerve branches, no significantdifferences were observed in the outcomes and complicationsbetween antegrade and retrograde dissection techniques [30].Postoperative complications reported in the current reviewinclude reactionary hemorrhage immediately after surgery[4] and transient facial nerve deficit which recovered in dura-tions ranging from one month to 6 months [4, 11, 14, 16, 17,32] (Table 1). Although there were no documented cases ofpermanent facial nerve injury, Calvo-Henriquez et al. [28]
reported a case of preoperative “House-Brackman GradeIII” facial nerve deficit, which persisted postoperatively.
In addition to the long-standing nature of the tumor andits large size, the currently reported case also presented withatypical histological findings. While the histological picturewas predominantly coherent with that ofPA characterizedby epithelial tissue dispersed in a chondroid and myxoidmatrix [34], there was marked squamous metaplasia and ker-atin cyst formation (Figure 4). These findings are unusual inPA of the parotid gland and lead to a high index of suspiciontowards a diagnosis of mucoepidermoid carcinoma or squa-mous cell carcinoma [35]. However, similar findings havebeen reported in the literature in PA arising in labial and pal-atal minor salivary glands, wherein malignant transforma-tion is highly suspected and ranges from 2 to 23% [6, 35].Squamous metaplasia of glandular cells is attributed to hyp-oxia within the growing tumor and combined with keratincysts; they mimic cutaneous appendages and are termed as“cystic pleomorphic adenoma with extensive adnexa-like dif-ferentiation” [35]. It has further been emphasized that theabove findings during the histological examination of sus-pected pleomorphic adenomas warrant meticulous histo-pathological evaluation to avoid surgical overtreatment [6,35]. Analyzing the histological findings in the present review,only one case was associated with cartilaginous metaplasia[10], without any evidence of malignant change, similar tothat observed in our case too. Nevertheless, malignant trans-formation was reported based on final histopathologicalexamination in 10 cases, including 5 cases of carcinomaexpleomorphic adenoma (CA-ExPA) [17, 20, 23, 24, 32],one case of adenocarcinoma along with PA [15], 3 cases ofmixed malignant tumor arising in PA [8, 12, 30], and onecase of metastasizing PA with renal metastasis [19](Table 1). Interestingly, one of the cases of CA-ExPA alsohad a malignant melanoma component, arising possiblyfrom melanocytes within parotid tissue [20].
Malignant transformation of PA is reported at around12% and comprises nearly 4% of all SGT [20]. According tothe World Health Organization (WHO) classification ofSGT, malignant tumors arising in PA were originally classi-fied either into CA-ExPA or the relatively rare mixed malig-nant tumor with epithelial and mesenchymal components [8,12]. While metastasizing PA, with metastatic lesions exhibit-ing histological characteristics of PA and no malignantchange was originally considered a malignant variant, it hasbeen relegated to the benign category as per the WHO classi-fication (2017) of SGT [36]. Although rare, metastasizing PAis frequently associated with multiple recurrences of the pri-mary tumor. Bhutta et al. [19] reported a case of metastaticrenal PA, with multiple postsurgical recurrences of theparotid PA in over a decade. Based on a retrospective studyof 221 patients with PA and 15 patients with CA-ExPA, Seoket al. [37] reported increasing age, regional lymph nodeinvolvement (>5mm), and MRI apparent diffusion coeffi-cient as the distinguishing clinical and radiographic featuresof CA-ExPA. In terms of histology, cellular atypia and stro-mal hyalinization have been regarded as the key delineatingfeatures of CA-ExPA from benign PA [36, 38]. Based onimmunohistochemistry (IHC), loss of expression of PLAG-
16 Case Reports in Dentistry
1 (pleomorphic adenoma gene-1) protein and overexpres-sion of Ki-67, p53, and HER-2 (human epidermal growthfactor receptor-2) are considered suggestive of malignanttransformation in otherwise benign PA [38, 39]. At a molec-ular genetic level, malignant transformation of PA is furthercharacterized by PLAG-1/HMGA-2 (High Mobility GroupAT-Hook 2) fusion and rearrangement, p53 mutation, andHER-2 amplification [36, 38, 39].
In the present review, PA with malignant transformationwas treated surgically, followed by radiotherapy for locore-gional disease and chemotherapy for distant metastases.Within postoperative follow-up periods ranging from 6months to 5 years, only one case of recurrent benign PAwas reported in the review [19]. Among tumors with malig-nant change, locoregional recurrence was reported in onecase of mixed malignant tumor [8], cervical lymph nodemetastasis was seen in 2 cases [12, 20], and distant metastasisto the anterior chest wall, lungs, liver, pelvis, and kidney wasobserved in 5 cases [12, 15, 19, 20, 30]. While there was nomortality associated with benign PA or its surgical treatment,3 patients with malignant transformation died within 6months after surgery as a result of metastatic disease [8, 15,20]. The longest recurrence-free follow-up for a giant parotidPA in the present review was 5 years [27], and this was stilllesser than the 7-year recurrence-free follow-up observed inour case.
4. Conclusion
Giant parotid PA is rare, and to the best of our knowledgefrom indexed literature, this is one of the very few casesreported in this geographical region (Saudi Arabia). Apartfrom its rarity, the present case is being reported for itslong-standing clinical presentation, successful surgical man-agement through ECD without any postoperative complica-tions or facial nerve deficit, atypical histologicalpresentation, and long-term recurrence-free follow-up. Inaddition to complete tumor removal, ECD helped preservethe integrity of facial nerve branches. Interestingly, the pres-ent case of giant parotid PA was benign in spite of associatedsquamous metaplasia and keratin cyst formation identifiedhistologically in the resected specimen. Nevertheless, thismandated a long-term follow-up of the patient. Therefore,based on this case report, clinicians must be aware of atypicalhistological presentation associated with parotid PA and plansuitable surgical management and follow-up, to achieve com-plete tumor removal and avoid morbidity. Lastly, attemptsmust be made to diagnose and manage PA at an early stageand before they reach gigantic proportions, through betterpublic health care initiatives and creating awareness amongall physicians and patients.
Ethical Approval
This case report was ethically approved by the ethical com-mittee at the College of Dentistry Research Center, King SaudUniversity, Riyadh, Saudi Arabia.
Consent
Informed consent was obtained from the patient.
Conflicts of Interest
The authors report no conflicts of interest with respect to thepublication of this article.
References
[1] M. G. Kato, E. Erkul, S. A. Nguyen et al., “Extracapsular dissec-tion vs superficial parotidectomy of benign parotid lesions,”JAMA Otolaryngology– Head & Neck Surgery, vol. 143,no. 11, pp. 1092–1097, 2017.
[2] A. Reinheimer, D. S. Vieira, M. M. Cordeiro, and E. R. Rivero,“Retrospective study of 124 cases of salivary gland tumors andliterature review,” Journal of Clinical and Experimental Den-tistry, vol. 11, no. 11, pp. e1025–e1032, 2019.
[3] O. E. Ogle, “Salivary gland diseases,” Dental Clinics of NorthAmerica, vol. 64, no. 1, pp. 87–104, 2020.
[4] O. B. Akintububo, O. K. Ogundipe, Z. Y. Kaltungo, M. I.Guduf, U. H. Pindiga, and Y. M. Abdullahi, “Giant parotidpleomorphic adenoma in a Nigerian male,” Nigerian Journalof Clinical Practice, vol. 19, no. 5, pp. 681–684, 2016.
[5] A. Rai, S. Sharma, P. Shrivastava, and M. Singh, “A huge pleo-morphic adenoma of the submandibular salivary gland,” BMJCase Reports, vol. 2018, 2018.
[6] S. Sharma, M. Mehendiratta, N. Chaudhary, V. Gupta,M. Kohli, and A. Arora, “Squamous metaplasia in pleomor-phic adenoma: a diagnostic and prognostic enigma,” Journalof Pathology and Translational Medicine, vol. 52, no. 6,pp. 411–415, 2018.
[7] P. Bonavolontà, G. Dell'Aversana Orabona, F. Maglitto et al.,“Postoperative complications after removal of pleomorphicadenoma from the parotid gland: a long-term follow up of297 patients from 2002 to 2016 and a review of publications,”The British Journal of Oral & Maxillofacial Surgery, vol. 57,no. 10, pp. 998–1002, 2019.
[8] C. Alvarez-Cañas and I. G. Rodilla, “True malignant mixedtumor (carcinosarcoma) of the parotid gland,” Oral Surgery,Oral Medicine, Oral Pathology, Oral Radiology, and Endodon-tology, vol. 81, no. 4, pp. 454–458, 1996.
[9] P. E. Lomeo, “Giant pleomorphic adenoma of the parotid,”Ear, Nose, & Throat Journal, vol. 75, p. 402, 1996.
[10] J. E. Buenting, T. L. Smith, and D. K. Holmes, “Giant pleomor-phic adenoma of the parotid gland: case report and review ofthe literature,” Ear, Nose, & Throat Journal, vol. 77, pp. 634,637–638, 640, 1998.
[11] J. Rodriguez-Ciurana, C. Rodado, M. Saez, and C. Bassas,“Giant parotid pleomorphic adenoma involving the paraphar-yngeal space: report of a case,” Journal of Oral and Maxillofa-cial Surgery : official journal of the American Association ofOral and Maxillofacial Surgeons, vol. 58, no. 10, pp. 1184–1187, 2000.
[12] S. Manuel, A. Mathews, K. Chandramohan, and M. Pandey,“Carcinosarcoma of the parotid gland with epithelial–myoe-pithelial carcinoma and pleomorphic sarcoma components,”British Journal of Oral and Maxillofacial Surgery, vol. 40,no. 6, pp. 480–483, 2002.
[13] D. Panoussopoulos, J. Yotakis, B. Pararas, G. Theodoropoulos,and K. Papadimitriou, “Giant pleomorphic adenoma of the
17Case Reports in Dentistry
parotid gland involving the parapharyngeal space treated by atotally extraoral transparotid approach,” Journal of SurgicalOncology, vol. 81, no. 3, pp. 155–157, 2002.
[14] M. N. de Silva, K. M. S. Kosgoda, W. M. Tilakaratne, andP. Murugadas, “A case of giant pleomorphic adenoma of theparotid gland,”Oral Oncology Extra, vol. 40, no. 3, pp. 43–45, 2004.
[15] T. Honda, Y. Yamamoto, T. Isago, H. Nakazawa, M. Nozaki,and T. Hirayama, “Giant pleomorphic adenoma of the parotidgland with malignant transformation,” Annals of Plastic Sur-gery, vol. 55, no. 5, pp. 524–527, 2005.
[16] L. Ruiz-Laza, P. Infante-Cossio, A. Garcia-Perla, J.-M. Hernandez-Guisado, and J.-L. Gutierrez-Perez, “Giantpleomorphic adenoma in the parapharyngeal space: report of2 cases,” Journal of Oral and Maxillofacial Surgery, vol. 64,no. 3, pp. 519–523, 2006.
[17] B. Sergi, A. Limongelli, E. Scarano, A. R. Fetoni, andG. Paludetti, “Giant deep lobe parotid gland pleomorphic ade-noma involving the parapharyngeal space. Report of threecases and review of the diagnostic and therapeuticapproaches,” Acta Otorhinolaryngologica Italica : Organo Uffi-ciale della Societa Italiana di Otorinolaringologia e ChirurgiaCervico-Facciale, vol. 28, no. 5, pp. 261–265, 2008.
[18] A. Takahama Jr., D. E. da Cruz Perez, J. Magrin, O. P. deAlmeida, and L. P. Kowalski, “Giant pleomorphic adenomaof the parotid gland,”Medicina Oral, Patologia Oral y CirugiaBucal, vol. 13, pp. E58–E60, 2008.
[19] M. F. Bhutta, L. Dunk, A. J. Molyneux, and A. Tewary,“Parotid pleomorphic adenoma with solitary renal metastasis,”British Journal of Oral and Maxillofacial Surgery, vol. 48, no. 1,pp. 61–63, 2010.
[20] M. K. Karpowicz, B. Shalmon, K. H. Molberg, and A. K. El-Naggar, “Melanoma in a carcinoma ex pleomorphic adenomaof the parotid gland: a case report and putative histogenesis,”Human Pathology, vol. 42, no. 9, pp. 1355–1358, 2011.
[21] M. A. Cetin, A. Ikinciogullari, G. Saygi, H. G. Hatipoglu,S. Koseoglu, and H. Dere, “Giant pleomorphic adenoma ofthe parotid gland,” The Turkish Journal of Ear Nose andThroat, vol. 22, no. 2, pp. 116–118, 2012.
[22] I. Morariu, A. Dias, and A. Curran, “Giant parotid pleomor-phic adenoma in parapharyngeal space causing severe obstruc-tive sleep apnoea,” Irish Medical Journal, vol. 105, no. 6,pp. 184-185, 2012.
[23] N. Yoshida, M. Hara, H. Kanazawa, and Y. Iino, “Large carci-noma ex pleomorphic adenoma of the parotid gland: a casereport and review of literature,” Journal of Oral and Maxillofa-cial Surgery, vol. 71, no. 12, pp. 2196.e1–2196.e6, 2013.
[24] A. E. Pamuk, C. Cabbarzade, H. Uner, R. Ö. Günaydın, andK. Kosemehmetoglu, “A neglected giant parotid gland mass:excision and reconstruction with facial nerve preservation,”Otolaryngologia Polska, vol. 68, no. 6, pp. 333–337, 2014.
[25] A. N. Datarkar and A. Deshpande, “Giant parapharyngealspace pleomorphic adenoma of the deep lobe of parotid pre-senting as obstructive sleep apnoea: a case report & review ofthe diagnostic and therapeutic approaches,” Journal of Maxil-lofacial and Oral Surgery, vol. 14, no. 3, pp. 532–537, 2015.
[26] M. Sajid, S. Rehman, and J. Misbah, “Giant pleomorphic ade-noma of the parotid gland,” Journal of the College of Physiciansand Surgeons–Pakistan, vol. 25, Supplement 2, pp. S110–S111,2015.
[27] A. Tarsitano, A. Pizzigallo, F. Giorgini, and C. Marchetti,“Giant pleomorphic adenoma of the parotid gland: an unusual
case presentation and literature review,” Acta Otorhinolaryn-gologica Italica : Organo Ufficiale della Societa Italiana di Otor-inolaringologia e Chirurgia Cervico-Facciale, vol. 35, no. 4,pp. 293–296, 2015.
[28] C. E. Calvo-Henriquez, A. Telmo-Mella, C. Dios-Loureiro, andC. Martin-Martin, “Giant pleomorphic adenoma of theparotid gland,” Acta Otorrinolaringologica Espanola, vol. 67,no. 6, pp. e40–e41, 2016.
[29] S. K. Swain, M. C. Sahu, and S. Mishra, “An ulcerated giantpleomorphic adenoma of the parotid gland – a case report,”Egyptian Journal of Ear, Nose, Throat and Allied Sciences,vol. 17, no. 2, pp. 111–114, 2016.
[30] T. N. Chao, C. H. Rassekh, S. B. Cannady, and V. A. LiVolsi,“Giant parotid carcinosarcoma arising in a pleomorphic ade-noma: facial nerve preservation by retrograde dissection,”OTO open, vol. 1, no. 3, p. 2473974X1771941, 2017.
[31] H. Alnofaie, T. Alshammeri, Y. Alturkistany, A. Aljabab, andA. Alweteid, “Giant pleomorphic adenoma of parotid glandin Saudi Arabia: a rare case report,” SN Comprehensive ClinicalMedicine, vol. 2, no. 8, pp. 1258–1263, 2020.
[32] Y. K. Pareek, D. Gupta, Y. Aseri, D. S. Rawat, B. K. Singh, andP. C. Verma, “Giant pleomorphic adenomas of parotid gland: acase series,” Indian Journal of Otolaryngology and Head &Neck Surgery, 2020.
[33] S. Jousse-Joulin, “Chapter 17 - salivary glands,” in EssentialApplications of Musculoskeletal Ultrasound in Rheumatology,R. J. Wakefield and M. A. D'Agostino, Eds., pp. 199–206,W.B. Saunders, Philadelphia, 2010.
[34] D. K. Das and J. T. Anim, “Pleomorphic adenoma of salivarygland: to what extent does fine needle aspiration cytologyreflect histopathological features?,” Cytopathology : officialjournal of the British Society for Clinical Cytology, vol. 16,no. 2, pp. 65–70, 2005.
[35] M. C. V. Goulart, P. Freitas-Faria, G. R. Goulart et al., “Pleo-morphic adenoma with extensive squamous metaplasia andkeratin cyst formations in minor salivary gland: a case report,”Journal of Applied Oral Science : Revista FOB, vol. 19, no. 2,pp. 182–188, 2011.
[36] R. R. Seethala and G. Stenman, “Update from the 4th edition ofthe World Health Organization Classification of Head andNeck Tumours: tumors of the salivary gland,” Head and NeckPathology, vol. 11, no. 1, pp. 55–67, 2017.
[37] J. Seok, S. J. Hyun, W. J. Jeong, S. H. Ahn, H. Kim, and Y. H.Jung, “The difference in the clinical features between carci-noma ex pleomorphic adenoma and pleomorphic adenoma,”Ear, Nose, & Throat Journal, vol. 98, no. 8, pp. 504–509, 2019.
[38] S. Di Palma, “Carcinoma ex pleomorphic adenoma, with par-ticular emphasis on early lesions,” Head and Neck Pathology,vol. 7, no. S1, pp. 68–76, 2013.
[39] M. Asahina, T. Saito, T. Hayashi, Y. Fukumura, K. Mitani, andT. Yao, “Clinicopathological effect of plag1 fusion genes inpleomorphic adenoma and carcinoma ex pleomorphic ade-noma with special emphasis on histological features,”Histopa-thology, vol. 74, no. 3, pp. 514–525, 2019.
18 Case Reports in Dentistry