Download - Salivary gland pathology
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Salivary Gland Tumors
Dr. Arsalan MalikAssistant Professor (Oral Pathology)
حيم الر حمن الر الله بسم
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Anatomy of Salivary Glands
Three major salivary glands
• Parotid gland (Stensen’s duct)
• Submandibular gland (warthin’s duct)
• Sublingual gland (Bartholin’s duct)
• Innumerable minor salivary glands in mucosa and oral cavity
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Functions of Saliva• Protection• Lubrication• Buffering• Digestion• Taste• Antimicrobial • Tooth integrity
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Normal histology of salivary gland
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Acinar cells of Salivary Glands
Classified as either:
• Serous cells: produce a thin watery secretion
• Mucous cells: produce a more viscous secretion
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Salivary gland secretory unit
• Composed of terminal acini
• Intercalated, striated and excretory ducts
• Myoepithelial cells
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Major Glands/Secretions
• Major SG are paired structures and include the parotid, submandibular and
sublingual
• Parotid: serous
• Submandibular: mucous & serous
• Sublingual: mucous
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Diseases of Salivary Glands
• Neoplastic
• Developmental
• Infectious
• Inflammatory
• Autoimmune
• Ischemic
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Salivary Gland Tumors
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Etiologic Factors
• Radiation exposure
• Genetic predisposition
• Tobacco
• Chemical carcinogens
• Viruses
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Salivary Gland Tumors• Incidence: • 6 % of head & neck neoplasms
• Age: 6 – 7th decades - peak incidence• Gender: female predilection• Site: • Parotid: 64 - 80% • Minor glands (palate): 9 -23%• Submandibular gland: 8 - 11% • Sublingual gland: < 1%
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Tumors of the salivary gland may arise from -- the salivary epithelium (the parenchyma) --or the supportive stroma (mesenchymal)
Benign parenchymal tumors are known as Adenomas Malignant tumors are known as adenocarcinomas .
Salivary gland tumors may arise form any cellular component including the basal cells ductal, striated intercalated ducts, acini and the myoepithelial cells.
Salivary gland Tumors
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Salivary Gland Tumors• Benign• Malignant
Relative proportion of malignancy increasing in the smaller glands (rule of thumb is the 25/50/75 rule)
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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BENIGN SAIVARY GLAND TUMORS
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General Characteristics• Grow slowly,
• Asymptomatic,
• Do not fluctuate in size
• Usually of long duration
• Present a single nodule
• Not fixed to overlying skin or mucous membrane
• Recurrent lesion may be multi- nodular
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Pleomorphic Adenoma• Benign glandular neoplasm
• Incidence: common
• 70% of salivary tumors
• Gender: female > male
• Age: 3-6th decades
• Site: parotid, palate, upper lip, buccal mucosa
• Symptoms: slow growing painless mass
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Pleomorphic Adenoma Gross Pathology:
- well circumscribed firm tan white solid or partially cystic mass
Histology: - ductal epithelial cells - myoepithelial cells - stroma: myxoid, chondroid, fibrohyaline
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Pleomorphic Adenoma
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Pleomorphic AdenomaTreatment:
• Surgical excision
• Superficial parotidectomy
• Prognosis: excellent
• Complications:
• recurrence – multifocal
• malignant transformation (5%)
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum)• Benign salivary gland tumor
• Incidence: common
• Gender: male > female
• Age: 5-7th decades
• Symptoms: painless mass
• Site: parotid, multi-focal/bilateral (14%)
• Etiology: smoking (8 fold risk)
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Warthin’s Tumor• Gross Pathology:• Well circumscribed cystic mass• Papillations • “machine oil fluid”
Histology: • Encapsulated cystic lesion• Papillary fronds• Oncocytic columnar cells• Lymphoid stroma
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Warthin’s Tumor
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Warthin’s TumorTreatment:• Surgical excision• Superficial parotidectomy• Prognosis: excellentComplications: • Recurrence – 6-12% (multicentric)• Association with other salivary tumors • Malignant transformation – extremely rare
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Oncocytoma
• Benign salivary gland neoplasm• Incidence: rare (1% of salivary tumors)• Site: parotid gland (85-90%)• Age: 6-8th decades• No gender predilection• Symptoms: painless mass (<4 cm)• Multifocal/bilateral
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Oncocytoma
• Encapsulated
• Trabecular-organoid
• Oncocytic epithelial cells
• Fibrous septae
• Clear cells
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OncocytomaTreatment
• Surgical excision
Prognosis
• Excellent
• Recurrence uncommon
• Oncocytic Adenocarcinoma - sinonasal tract
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Oncocytoma• Electron Microscopy:
-Mitochondrial hyperplasia
-60% of cell volume
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Ductal Papillomas
Present in three forms
• 1-Simple ductal papilloma
• 2-Inverted ductal papilloma
• 3-Sialadenoma papilliferum
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Simple ductal papilloma
-Exophytic lesion, papillary surface and pedunculated base
-Reddish in color present on palate or buccal mucosa
-It consist of non-keratinized epithelium, columnar, supported by a core of vascular fibrous connective tissue
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Inverted ductal papilloma
-Present as a nodule of oral mucosa of adults. No
distinctive clinical features
-Histologically it consist of squamous, cuboidal,or
columnar cells which proliferate into duct to form a
bulbous masses.
Mucous cells and micro cyst with mucous may be
seen
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Sialadenoma Papilliferum
-The lesion occurs in adults
-Exophitic papillary lesion of hard palate
-Luminal layer of columnar cells on cuboidal
basal layer.
-Connective tissue papillae contain plasma
cells
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Monomorphic adenoma
• Consists of single epithelial cells type
• Basal cell, canalicular, sebaceous, glycogen-rich, clear cell
• Most common types are
- Basal Cell Adenoma
- Canalicular Adenoma
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Canalicular Adenoma
• Benign salivary gland neoplasm
• Monomorphic adenoma
• Site: upper lip (75%)
• Age: 7th decade
• Gender: female predilection
• Symptoms: slow growing mass
• Multifocal
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Canalicular Adenoma
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Canalicular AdenomaTreatment
• Conservative surgical excision
• Enucleation not recommended
Prognosis
• Excellent
• Rare recurrence
• Can be misdiagnosed as a malignancy
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Basal Cell Adenoma• Benign salivary gland neoplasm
• Monomorphic adenoma
• Incidence: 2% of salivary gland tumors
• Site: parotid gland (75%)
• Age: 4-9th decades
• Gender: female predilection (2:1)
• Symptoms: slow growing mass (< 3cm)
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Basal Cell Adenoma
• Solid
• Most common
• Solid nests of tumor cells
• Uniform, hyperchromatic, round nuclei,
indistinct cytoplasm
• Peripheral nuclear palisading
• Scant stroma
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Basal Cell Adenoma
Trabecular pattern `Elongated anastomosing cords of basal
cells, surrounded by connective tissue stroma.
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Basal Cell Adenoma
Tubular Pattern `Basaloid cells surrounds the duct like
structure.
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Basal Cell Adenoma
Membranous or dermal analogue adenoma
`Tumor islands moulded in jig saw
puzzle fashion surrounded by
hylinized basal lamina
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Basal Cell AdenomaTreatment• Complete surgical excision
Prognosis• Excellent• Recurrences may occur• Malignant transformation is rare • Hybrid tumor
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Malignant Epithelial Tumors
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Malignant Epithelial Tumors Mucoepidermoid carcinoma – 29% Adenocarcinoma, NOS –
27% Acinic cell carcinoma –
17% Polymorphous low grade
carcinoma – 19.6% Adenoid cystic carcinoma – 7.5%
Basal cell adenocarcinoma – 2.9%
Epithelial myoepithelial carcinoma – 1%
Clear cell carcinoma – 1%
Salivary duct carcinoma – 0.5%
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Malignant salivary gland tumors
• Shorter duration than benign
• Grow rapidly or history of slow growth with sudden rapid activity
• Fixed to surrounding tissues
• Overlying skin or mucous membrane may be ulcerated or inflamed
• Surface talengectasia
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Malignant salivary gland tumors
• Parotid gland tumors associated with facial nerve paralysis or neurological
symptoms
• Regional lymph nodes may be enlarged
• Palate and retromolar gland tumors infiltrate bone,produce radiolucencies and
loosening of teeth
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Salivary Gland Tumor Staging
• T1: tumor < 2 cm
• T2: tumor 2 - 4cm
• T3: tumor > 4 cm or extraparenchymal
• T4a: invades skin, mandible, ear canal or facial nerve
• T4b: tumor invades skull base, pterygoid plates or encases carotid artery
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Mucoepidermoid Carcinoma• Malignant epithelial salivary gland tumor• 2nd most common salivary gland tumor • 30% of malignant salivary gland tumors• Age: 2nd – 7th decades• Gender: slight female predilection• Site: parotid gland, palate• Etiology: radiation exposure• Asymptomatic swelling
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Mucoepidermoid Carcinoma• Gross pathology
• Well-circumscribed to partially encapsulated to unencapsulated
• Solid tumor with cystic spaces
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Mucoepidermoid Carcinoma
• Histology—Low-grade
• Mucus cell > epidermoid cells
• Prominent cysts
• Mature cellular elements
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Mucoepidermoid Carcinoma
• Histology—Intermediate- grade
• Mucus = epidermoid
• Fewer and smaller cysts
• Increasing pleomorphism and
mitotic figures
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Mucoepidermoid Carcinoma
• Histology—High-grade
• Epidermoid > mucus
• Solid tumor cell proliferation
• Mistaken for SCCA
• Mucin staining
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Mucoepidermoid Carcinoma
• Histology—High-grade
• Epidermoid > mucus
• Solid tumor cell proliferation
• Mistaken for SCCA
• Mucin staining
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Mucoepidermoid CarcinomaTreatment
Influenced by site, stage, grade
Stage I & II
Wide local excision
Stage III & IV
Radical excision
+/- neck dissection
+/- postoperative radiation therapy
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Prognosis• Recurrence
• Metastasis – lymph nodes, lung, bone, skin
• Low to intermediate grades
• – good prognosis ( 90% 5 year survival )
• High grade
• – poor prognosis (40% 5 year survival)
• Site: submandibular, floor of mouth, tongue
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Acinic Cell Carcinoma
• 2nd most common parotid and pediatric malignancy
• 5th decade
• F>M
• Bilateral parotid disease in 3%
• Presentation
• Solitary, slow-growing, often painless mass
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Acinic Cell Carcinoma
• Gross pathology
• Well-demarcated
• Most often homogeneous
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Histopathology
• Circumscribed
• Variable growth patterns
• Variable cytology
• Low grade tumor
• Scant stroma
• Lymphoid infiltrate
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Histopathology
• Histology
• Solid and microcystic patterns
• Most common
• Solid sheets
• Numerous small cysts
• Polyhedral cells
• Small, dark, eccentric nuclei
• Basophilic granular cytoplasm
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Acinic Cell Carcinoma Treatment:
- surgical excision Prognosis: - low-grade malignancy
- 12% recur - 8% metastasize - 6% mortality - prognosis is better for minor gland tumors Undifferentiated carcinoma component (rare) Difficult diagnosis for pathologist
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Adenoid Cystic Carcinoma• Overall 2nd most common malignancy
• Most common in submandibular, sublingual and minor salivary glands
• M = F
• 5th decade
• Presentation
• Asymptomatic enlarging mass
• Pain, paresthesias, facial weakness/paralysis
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Adenoid Cystic Carcinoma• Gross Pathology:
• - uncapsulated firm solid tan mass
• Histology:
highly infiltrative
small hyperchromatic cells
cribriform (“Swiss cheese”), tubular, solid
mucohyaline stroma
Perineural invasion
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Adenoid Cystic Carcinoma• Gross pathology
• Well-circumscribed
• Solid, rarely with cystic spaces
• infiltrative
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Adenoid Cystic Carcinoma• Histology—
• cribriform pattern
• Most common
• “swiss cheese” appearance
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Adenoid Cystic Carcinoma• Histology—tubular pattern• Layered cells forming duct-
like structures• Basophilic mucinous
substance
• Histology—solid pattern• Solid nests of cells without
cystic or tubular spaces
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Adenoid Cystic CarcinomaTreatment
Complete local excision
Tendency for perineural invasion: facial nerve sacrifice
Postoperative Radiations
Prognosis
Local recurrence: 42%
Distant metastasis: lung
Indolent course: 5-year survival 75%, 20-year survival 13%
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Salivary Gland TumorsBenign
► Pleomorphic adenoma► Warthin`s tumor ► Oncocytoma► Myoepithelioma ► Ductal papilomas► Monomorphic adenoma1. Basal cell adenoma 2. Canalicular adenoma
Malignant ►Mucoeidermoid carcinoma►Acinic cell carcinoma►Adenoid cystic carcinoma►Polymorphous low grade adenocarcinoma►Carcinoma arising in pleomorphic adenoma
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Polymorphous low grade adenocarcinoma• Malignant epithelial neoplasm
• Oral cavity - minor glands
• Age: wide range – 6-8th decades
• Female gender predilection
• Site: palate (65%), lip, buccal mucosa
• Symptoms: painless swelling
• Duration: weeks to years
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Polymorphous low grade adenocarcinoma• Malignant epithelial neoplasm
• Oral cavity - minor glands
• Age: wide range – 6-8th decades
• Female gender predilection
• Site: palate (65%), lip, buccal mucosa
• Symptoms: painless swelling
• Duration: weeks to years
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Polymorphous low grade adenocarcinoma• 2nd most common malignancy in
minor salivary glands• 7th decade• F > M• Painless, submucosal mass• Morphologic diversity
• Solid, glandular, cribriform, ductular, tubular, trabecular, cystic
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Polymorphous low grade adenocarcinoma• Histology• Isomorphic cells, indistinct borders,
uniform nuclei• Peripheral “Indian-file” pattern
• Treatment• Complete yet conservative excision
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Lymphoepithelial Carcinoma• Rare• High grade/poorly differentiated carcinoma• Lymphoid stroma• Asians, Greenlanders• Epstein-Barr virus• Prognosis - guarded
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Lymphoepithelial Carcinoma• undifferentiated tumor associated with
a dense lymphoid stroma
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Salivary Adenocarcinoma NOS• Some tumours still defy the current classification of salivary gland
tumours• These are labelled as Salivary Adenocarcinoma Not Otherwise
Specified (NOS)
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Treatment & Prognosis
• Early stage, well differentiated tumours appear to have a better
prognosis
• The survival rate is better for tumours of oral cavity as compared to
tumours of major salivary gland.