cysts &tumors of salivary glands /certified fixed orthodontic courses by indian dental academy

CYSTS AND TUMORS OF THE SALIVARY GLANDS

INDIAN DENTAL ACADEMY

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CYSTS OF THE SALIVARY GLANDS Mucocele. Ranula.


B) MUCOCELES

Mucocele is clinical term that describes swelling caused by the accumulation of saliva at the site of a traumatized or obstructed minor salivary gland duct or it can be simply due to obstructed salivary gland duct.

Mucoceles can be classified as EXTRAVASATION type and RETENTION type.

A large mucocele in the floor of the mouth is called as RANULA.


ETIOLOGY

Extravasation type of mucocele is believed to be the result of trauma to a minor salivary gland excretory duct.

Laceration of duct results in pooling of saliva in the adjacent sub mucosal tissue and consequent swelling.

Retention type is caused by obstruction of minor gland duct by calculus or contraction of scar around an injured duct

The blockage of salivary flow causes the accumulation of saliva and dilation of the duct, so eventually an aneurysm like lesion forms which is lined by epithelium of the dilated duct.


CLINICAL FEATURES

Extravasation type commonly occur in lower lip where trauma is common followed by buccal mucosa, tongue, floor of the mouth, retro molar area etc.

Mucous retention cysts are commonly found on the palate or floor of the mouth.

Mucoceles often present as discrete pain less smooth surfaced swellings that can range from a few mm to a few cm in diameter.

Superficial lesions have a characteristic blue hue.

Deeper lesions may be more diffuse and covered by normal mucosa with out blue hue.

The lesions may vary in size over time.


TREATMENT

Surgical excision, to prevent recurrence removal of associated minor salivary gland is essential.

Aspiration of fluid does not provide long term benefit.

Intra lesional injections with corticosteroids are helpful to treat mucocele.


C) RANULA

May be extravasation or retention types. Seen in floor of the mouth as a large mucocele. Associated with sub lingual salivary gland duct.

Etiology:

Considered due to trauma commonly and less commonly due to retention of saliva due to obstruction or aneurysm.

A sarcoid associated ranula is also reported.


CLINICAL FEATURES

As name suggests it resembles the swollen belly of a frog.

Lesion present as painless, slow growing, soft movable mass located in the floor of the mouth.

It is formed on one side of lingual frenum, some times crosses the mid line.

Ranulas have typical bluish hue.

Deep lesions terminate through mylohyoid muscle and extend along the facial planes referred to as plunging ranula. And can become large, extending into neck.


TREATMENT

Surgical marsupialization procedures unroof the lesion and are the treatment of choice in smaller lesions.

Excision in case of large lesions and also in recurrence.

Intralesional injections of corticosteroids are successful.


TUMORS OF THE SALIVARY GLAND Majority about 80% of salivary gland tumors arise in the parotid

gland, the submandibular gland accounts for 10 to 15 % and the remaining 5 to 10 % arise in minor salivary glands.

About 80% of parotid and 50% of submandibular tumors are Benign in contrast, more than 60% of tumors in sublingual and minor salivary glands are Malignant.

The risk of malignancy increases as the size of the tumor decreases. And over 85% of tumors occur in adults.


CLASSIFICATION

BENIGN TUMORS – Pleomorphic adenoma. Monomorphic adenoma. Oncocytoma. Basal cell adenoma. Myoepithelioma. Ductal papilloma. Papillary cystadenoma. Lymphomatosum. MALIGNANT TUMORS – Mucoepidermoid carcinoma. Adenocystic carcinoma. Acinic cell carcinoma. Adenocarcinoma. Lymphoma.


SHAFERS CLASSIFICATION

BENIGN TUMORS:1) Pleomorphic adenoma (Mixed tumor).

2) Monomorphic adenoma.

3) Basal cell adenoma.

4) Canalicular adenoma.

5) Papillary cystadenoma lymphomatosum (Warthin’s tumor, Adenolymphoma).

6) Oxyphilic adenoma (Oncocytoma, Acidophilic adenoma).

7) Myoepithelioma.

8) Ductal papillomas.

9) Benign lymphoepithelial lesion (Mickulicz’s disease).

10) Sjogren’s syndrome (Sicca syndrome, Gougerat – sjogren syndrome).

MALIGNANT TUMORS:1) Malignant pleomorphic adenoma (Malignant

“Mixed” tumor, Carcinoma Ex pleomorphic adenoma).

2) Adenoid cystic carcinoma (Cylindroma, Adeno cystic carcinoma, Adeno cystic basal cell carcinoma, Pseudo adenomatous basal cell carcinoma, Basaloid mixed tumor).

3) Acinic cell carcinoma (Acinar cell or serous cell adenoma and Adenocarcinoma).

4) Mucoepidermoid carcinoma.

5) Central mucoepidermoid carcinoma of the jaw.

6) Clear cell carcinoma.

7) Adenocarcinoma of miscellaneous forms.

8) Epidermoid carcinoma (Squamous cell carcinoma).

9) Necrotizing sialometaplasia.


FOOTE & FRAZELL, 1934

BENIGN:1) Mixed tumor.

2) Papillary cystadenoma lymphomatosum.

3) Oxyphilic adenoma.

4) Sebaceous cell adenoma.

5) Benign lymphoepithelial lesion.

6) Unclassified.

MALIGNANT:1) Malignant mixed tumor.

2) Mucoepidermoid tumor.

3) Squamous cell carcinoma.

4) Adenocarcinoma Adenoid cystic Trabecular or solid Anaplastic Mucous cell Pseudoadamanite Acinic cell

5) Unclassified.


WHO CLASSIFICATION, 19721) Epithelial tumors A) Adenomas i) Pleomorphic adenoma ii) Monomorphic adenoma a) Adenolymphoma b) Oxyphilic adenoma c) Other B) Mucoepidermoid tumor C) Acinic cell tumor D) Carcinomas i) Adenoid cystic carcinoma ii) Adenocarcinoma iii) Epidermoid carcinoma iv) Undifferentiated carcinoma v) Carcinoma in pleomorphic adenoma2) Non epithelial tumors3) Unclassified tumors4) Allied conditions a) Benign lymphoepithelial lesions b) Sialosis c) Oncocytosis


BENIGN TUMORS


A) PLEOMORPHIC ADENOMA Etiology and prevalence: Most common tumor of salivary

glands, accounts for 60% of all salivary gland tumors.

It is a mixed tumor because it consists of both epithelial and mesenchymal elements. About 85% of these tumors found in parotid gland, and 8% found in submandibular glands and the remaining in sub lingual and minor salivary glands.

Pleomorphic adenomas can occur at any age.

The incidence is in 4th to 6th decades of life.

Also represents most common salivary neoplasm in children.


CLINICAL PRESENTATION Appear as painless, firm and mobile masses that rarely ulcerate the overlying skin

and mucosa.

In the parotid gland, the neoplasm are slow growing and usually occur in posterior inferior aspect of the superficial lobe mixed tumors in submandibular glands presents as well defined palpable masses.

Intra orally the tumors occur on the palate, followed by the upper lip and buccal mucosa.

Adenomas may vary in size depending on gland in which they are located.


PATHOLOGY

Appears as firm smooth mass within a pseudo capsule, histologically, demonstrates both epithelial and mesenchymal elements.

The epithelial cells make up a trabecular pattern within a stroma of chondroid, myxoid, osteoid, or fibroid. Thus the name pleomorphic tumor or mixed tumor.

One characteristic of this adenoma is the presence of microscopic projections of the tumor outside the capsule, and if these are not removed with the tumor, the lesion will recur.


TREATMENT

Consists of surgical removal with adequate margins, this tumor requires wide resection due to its recurrence.

A superficial parotidectomy is sufficient for the majority of these lesions.

Lesions in the sub mandibular gland are treated by removing the entire gland.


B) MONOMORPHIC ADENOMA A monomorphic adenoma is a tumor that is composed of

predominantly of one cell type, as opposed to a pleomorphic type.

Management of monomorphic adenoma is as same as the pleomorphic.


C) PAPILLARY CYSTADENOMA LYMPHOMATOSUM Also known as warthin’s tumor, and is

the second most common benign tumor of parotid gland.

Almost always located in the parotid in the inferior pole of the gland, posterior to the angle of the mandible.

Males usually affected and occur in 5th and 8th decades.

Can occur bilaterally also.

Tumor presents as a well defined slow growing mass in the tail of the parotid gland.

Usually painless unless super infected.


This tumor is visible in scintigraph as it contains oncocytes which takes up the technetium 99 dyes.

The gross appearance of the tumor is smooth with a well defined capsule.

Cutting a specimen reveals cystic spaces filled with thick mucinious material.

Treatment of this tumor is excision with a margin of normal tissue because of its easily accessible location.

Superficial parotidectomy is also performed in case of large lesions.


D) ONCOCYTOMA

Less common benign tumor that make up 1% of all salivary gland neoplasm.

It contains large granular acidophilic cells called as oncocytes, so the name oncocytoma.

These are usually solid round tumors that are seen in any of the major salivary glands and are rare intra orally.

Commonly found in superficial lobe of the gland.

Second most common tumor that occur bilaterally after warthins tumor.


Grossly these tumors appear non cystic and firm.

Histologically consists of brown granular eosinophillic cells.

Malignant counter part can occur which are aggressive lesions.

Oncocytomas demonstrate very slow growth rate and benign course, so superficial parotidectomy with preservation of facial nerve is the treatment of choice.

Smaller lesions can be removed totally leaving normal tissue.

Recurrence is rare.


E) BASAL CELL ADENOMA Slow growing painless masses accounts for 1 to 2% of

salivary gland adenomas.70% occur in parotid gland and adenomas of minor salivary glands occur mostly in the lips.

Histologically three variants are demonstrated they are, solid, trabecular-tubular, and membranous.

Solid form consists of islands of basiloid cells. A nucleus is in normal size and is basophilic with minimal cytoplasmic material.


The trabecular- tubular form consists of trabecular chords of epithelium and the membranous form is multilocular and 50% of the lesions are encapsulated and tends to grow in clusters.

Lesions are removed by conservative surgical excision extending into normal tissue.


F) MYOEPITHELIOMA

Palate is most common intra oral site, no gender predilection exists.

Lesions tend to occur in adults, with average age being 53 years.

Lesion present as well circumscribed asymptomatic slow growing mass.

Consists of spindle shaped cells, plasmacytoid cells, or combination of two. Diagnosis is based on presence of myoepitheloid cells.


This tumor is epithelial in origin and best demonstrated by immunohistochemical staining for actins, cytokeratin, and S-100 protein.

Surgical excision including a border of normal tissue is the treatment of choice.


G) DUCTAL PAPILLOMA

Arise from excretory ducts of minor salivary glands.3 forms as simple (intercalated), inverted ductal, and sialadenoma.

Simple ductal papilloma: presents as exophytic lesion with pedunculated base. Lesion has a reddish colour.

Microscopically reveals epithelium lined papillary fronds projecting into cystic cavity with out proliferating into walls of the cyst. Local surgical excision is the recommended treatment.

Inverted ductal papilloma: occurs in minor salivary glands, presents as sub mucosal nodule that is similar to fibroma or lipoma. Microscopically same as above. And surgical excision is the treatment.


Sialadenoma papilliferum: Analogous to syringocystadenoma papilliferum of the skin.

An adult male predilection exists; occur between 5th and 8th decades of life.

Lesion occurs on palate and buccal mucosa and presents as a painless exophytic mass.

Clinically resembles a papilloma.

Microscopically lesion shows epithelium lined papillary projections supported by fibro vascular connective tissue, forming a series of clefts with in the lesion.


MALIGNANT

TUMORS


A) MUCOEPIDERMOID CARCINOMA Most common malignant tumor of the salivary glands.

Men and women are equally affected and the highest incidence occurs in 3rd and 5th decades of life.

This lesion consists of both epidermal and mucous cells and is classified as either high grade or low grade, depending on the ratio of epidermal cells to mucous cells.

A low grade tumor has a higher ratio and is less aggressive lesion even tough they have the ability to metastasis and local invasion, they behave like benign tumors.

A high grade form is believed to be more malignant and has poorer prognosis.


CLINICAL FEATURES

Clinical course depends on its grade. I.e., a low grade tumor undergo a longer period of painless enlargement where as a high grade tumor often demonstrate rapid growth and higher like hood of metastasis.

Pain and ulceration of overlying tissue are occasionally associated with this tumor.

If the facial nerve is involved the patient may exhibit a facial palsy.


PATHOLOGY

Macroscopically, low-grade mucoepidermoid carcinomas are usually small and partially encapsulated.

After sectioning this low grade tumors demonstrate a mucinous fluid where as a high grade lesions are usually solid in appearance.

Microscopically, low grade lesions consist of mucoid cells with interspersed epithelial strands, high grade tumors consists of epithelial and few mucinous cells.


TREATMENT

Low grade lesions are treated with superficial parotidectomy, where as high grade lesions should be aggressively treated to avoid recurrence.

Neck dissections may be performed for lymph node removal and staging in high grade lesions.

Post operative radiotherapy has been shown to be useful adjunct in treating the high grade tumor.


B) ADENOID CYSTIC CARCINOMA Most common malignant tumor of minor and sub

mandibular salivary glands.

50% occurs in minor glands, affects men and women equally and occurs in 5th decade of life.


CLINICALLY

Present as a firm unilocular mass in the gland, tumor is painful occasionally and has a propensity for peri neural invasion thus it can extend beyond obvious tumor margin.

Intra oral tumor exhibit mucosal ulceration which is a distinguishing feature from a benign mixed tumor.

Radio graphically the tumor reveals extension into adjacent bone.

Metastasis’s into lungs is more common than regional lymph node metastasis.


PATHOLOGY

Tumor is unilocular and either partially encapsulated or non encapsulated.

Microscopically the cells are small and cubiodal, with dense chromatin.

Pseudo cystic spaces filled with a cellular material is the characteristic feature of this tumor.


TREATMENT

Radical surgical excision of the lesion is the treatment of choice because of local invasion.

Neutron beam radiation has shown more effective than photon beam therapy.

Factors affecting the long term prognosis of the treatment are the size of primary lesion, its anatomical location, presence of metastasis at the time of surgery and facial nerve involvement.


C) ACINIC CELL CARCINOMA Represents about 1% of all salivary gland tumors, about

90 to 95 % are seen in parotid gland and remaining located in the submandibular gland.

More seen in women in 5th decade.


CLINICALLY

Present as slow growing masses, pain is present.

The superficial lobe and inferior lobe of parotid are the frequent sites.

Occur bilaterally in 3 % of cases.


PATHOLOGY

Well defined mass that is often encapsulated.

And two types of cells can be seen microscopically, as similar to acinar cells in the serous glands are seen adjacent to cells with a clear cytoplasm.

Which are seen positive in periodic acid Schiff stain.


TREATMENT

Long term survival is not favorable.

Treatment consists of superficial parotidectomy with facial nerve preservation if possible.

Total gland removal is treatment of choice in tumor of submandibular gland.


D) ADENOCARCINOMA

Any tumor arising from salivary duct epithelium is considered as Adeno carcinomas.

These are divided into discrete entities based on structure and behavior.

Clarification of the type with a histological description should be obtained in order to determine the appropriate treatment approach.


E) LYMPHOMA

Primary lymphomas of the salivary glands arise from lymph tissues with in the glands.

The major forms of lymphoma are non Hodgkin’s and Hodgkin’s disease.

The parotid gland is most commonly involved followed by sub mandibular gland.


CLINICALLY

Present as painless gland enlargement or adenopathy


TREATMENT

Superficial parotidectomy, radiation therapy, chemotherapy or a combination of the two depending on the staging of the lymphoma.


ABSCENCE OF GLAND DUE TO SURGERY OR TRAUMA


A) PAROTIDECTOMY

Surgical treatment for most of the low-grade salivary gland tumors consists of superficial parotidectomy as to preserve the facial nerve and their location at tail region.

For high grade tumors a total parotidectomy is done.

Complications occurring after parotidectomy include permanent, partial or total facial nerve paralysis, temporal nerve palsies, salivary fistulas or sialocele are all common complications. (Sialocele is a palpable collection of fluid formed when the edge of the parotid gland capsule is cut and the gland continues to leak fluid.)


Frey’s syndrome is common complication of parotidectomy.

This syndrome presents as gustatory sweating (patient flush or sweat with salivary stimulation due to mix of post gang ionic sympathetic fibers of sweat glands with that of regenerating post gang ionic secretary parasympathetic fibers to the sweat glands )

Frey’s syndrome occurs 30 to 60% of patients who have undergone parotidectomy.

The treatment of this disorder consists of tropical application of anti cholinergic, and also botulinum toxin injections are also used.

Xerostomia is most common complication.


B) SUB MANDIBULAR / SUBLINGUAL AND MINOR SALIVARY GLAND

SURGERY Submandibular, sub lingual salivary gland removal leads

to loss of salivary flow resulting in xerostomia and risks like hemorrhage, infections, injury to hypoglossal, lingual or marginal mandibular nerves.

Minor salivary gland removal depends on location and extent of disease.

Complete excision is desirable for benign tumors and for malignant tumors complete maxillectomy or composite resection is recommended.


LAB INVESTIGATIONS

SALIVA AND ITS ROLE AS A SCREENING TOOL

Saliva is a convenient fluid used for diagnostic purposes and has obvious benefits over plasma because of its ease in collection the samples and its non invasive, non stressful procedures for the patient.

Saliva can be used to determine the profile of the infection of the oral cavity with pathogens such as Candida as well as giving lactobacillus and streptococcus mutant’s scores.


COLLECTION OF SALIVA / TECHNIQUE Saliva is collected by 3 different methods they are PAROTID COLLECTOR SEGREGATOR AND COLLECTION OF WHOLE SALIVA BY , Draining technique,

spitting and suction methods


PAROTID COLLECTOR

Developed by Lashley in 1916. This makes possible the collection of parotid fluid uncontaminated by oral contents.

Composed of two concentric circles made of plastic or metal. The centre circle is designed such that it fits over the opening of stensons duct and is connected to a graduated collecting tube.

The outer concentric circle is attached to a rubber bulb, which exhausts air from the outer circle, when collector is held in place and draws the cheek surrounding the opening of stensons duct into it.

This cannot be used in sub mandibular and sub lingual glands because of their different anatomical locations.


SEGREGATOR

Developed by Schneyer which allows the collection of saliva from sub mandibular and sub lingual glands. This also made of plastic or metal constructed on a stone model for each individual.

On this a pre formed basic plastic collector is utilized then it is covered by a rubber base impression material and placed on the floor of the mouth beneath the tongue. In 5 minutes the impression is removed and a recess is made on the impression over the opening of Wharton’s duct and a plastic collecting tube is attached.

The collector stays in position when the patient places his tongue against the lingual surface of the lower incisors

This may be sorted out and reused for individual patient which collects saliva from sub mandibular and sub lingual glands.


COLLECTION OF WHOLE SALIVA

For this the patient is asked to suck on sour candy or sour grapes to stimulate the salivary flow. this can also be done by asking the patient to chew on cimer paraffin or rubber bands and can also be done by swabbing 2% citric acid solution on the back of tongue at 15 minutes interval. Then the saliva is collected by one of three methods.

SPITTING of saliva into a collecting funnel at regular intervals can be encouraged by the patient.

SUCTION by using a saliva ejector which is applied orally in the area of lower incisors and the aspirated fluid is collected after the patient has remained quits for fixed time period.


DRAINING METHOD : Materials used are, a watch, weight machine with 2 digits, a plastic

disposable cups, a saliva stimulator like paraffin and a metronome.

Patient is seated in relaxed position with his/ her head slightly tilted forward. After an initial swallowing action, the patient is instructed to allow saliva to passively drawn from the lower lip into the pre weighed plastic cup.

The collection starts at time zero and at the end of the collection period, residual saliva is expectorated from mouth into the cup.

Saliva containing cup is reweighed and the flow rate is calculated in gm / mts which is equivalent to ml / mts.

Collection of stimulated saliva is performed after collection of unstimulated following the same procedure, with exception of shorter collection time and application of chewing stimulus.

Every 30 sec, the patient is allowed to drip saliva into the cup and then collection continues. Measurement is done after 15 mts for unstimulated saliva and 5 mts for stimulated saliva.


Normal salivary flow rate is 1.0 – 1.5 ml / mts for stimulated saliva. And for unstimulated saliva, the flow rate is 0.3 ---- 0.5 ml /min.

If the unstimulated flow is less than 0.1 ml/min, then diagnosis for hypo salivation is marked out , and if stimulated flow rate is measured less than 0.5 ml/min or less for women and 0.7 ml/min in men , then diagnosis for salivary gland dysfunction is made and further investigations are carried out.

Thus saliva can serve as an excellent tool for determining various substances such as drugs, hormones and infections of the oral and salivary glands.


DIAGNOSIS IS ALSO CONFIRMED BY CERTAIN DIAGNOSTIC STUDIES

SIALOMETRY: Deals with estimation of salivary flow rates by draining method.

SIALOGRAPHY : Non specific test, in which a radio opaque dye is injected into the duct (such as iodine based dye) and a radiograph is taken which shows if the duct is constricted, dilated or there is any calculus formation.


SALIVARY SCINTISCANNING: Non invasive procedure, examines all major salivary

glands Technetium-99 is used which emits gamma radiation, and is associated with small amount of radiation hazard and is expensive procedure, not always used.

IMAGING: Chest radiography to rule out sarcoidosis. Ultrasonography to exclude sjogrens and neoplasm MRI scanning to exclude sjogrens.


SALIVARY GLAND BIOPSY: To rule out suspicion of organic disease of salivary glands.

If the dry mouth condition has no evidence of reduced flow or salivary gland.

Disorder, then there may be a Psychological reason for the complaint.


SALIVARY GLAND IMAGING


I. PLAIN FILMS

Parotid stones are almost always radiolucent.

Submandibular stones are nearly always radio-opaque.


II. PANAROMIC RADIOGRAPHY AND OCCLUSAL RADIOGRAPHY These are conventional radiographic procedures used to

rule out stones in gland structure and ducts.

Major advantage by this is it is easily affordable, and chair side decision making can be possible.

Disadvantage is poorly calcified stones and smaller sialoliths are not visualized.


III. SIALOGRAPHY

Radiographic visualization of salivary gland following retrograde instillation of soluble contrast media into the ducts of glands is known as sialography.

This was one of the oldest imaging procedures which was first mentioned by CARPY in the year 1902.

Later BARSONY & USLENGI in 1925 separately described sialography as a diagnostic tool.

Salivary ductal obstruction, whether by a sialolith or stricture can easily be visualized. When patient presents with history of rapid and acute onset of painful swelling of single gland upon eating, then this is the indicated imaging technique.

Can be performed on both sub mandibular and parotid glands with oil and water based contrast media containing iodine as main substrate.


Oil based media has its own self limitations as it is not diluted in saliva and allows for maximum opacification of ductal and acinar structures. But residues of oil media can induce granulomas at the site.

Water based media is soluble in saliva and can diffuse into the glandular tissue resulting in reduced radiographic density and poor visualization of peripheral ducts.

Recently higher viscosity water based medias are available that allows better visualization of ductal structures.

Routine radiographic procedures like Panoramic, Lateral oblique, Anteroposterior views and Puffed cheek AP views reveal ductal architecture after contrast media induction as a LEAFLADEN TREE (leaf less tree) appearance.


Non opaque sialoliths appear as Voids, and in sialedinites and sjogrens sialoliths appear as focal collections of contrast media with in the gland.

Progression of severity is visualized as punctuate, gloubular and cavitary patterns. This imaging technique is the choice for delineating ductal anatomy and for identifying and localizing sialoliths.

It is also a valuable tool in pre surgical planning prior to removal of salivary mass.

It is contraindicated in active infections and allergic condition to contrast media.

This also provides No quantification.


IV. ULTRA SONOGRAPHY

Due to the superficial location of the parotid and submandibular glands, these are easily visualized by ultra sonography.

Indicated for biopsy guiding, mass detection and is best used in differentiating between intra and extra glandular masses as well as cystic and solid lesions.

Solid benign lesions present as well circumscribed Hypo echoic intraglandular mass.

USG can demonstrate the presence of abscess in a acutely inflamed gland and also sialoliths, which appear as Echogenic densities that exhibit acoustic shadowing.


Parenchymal homogenecity in sjogrens syndrome was first reported by ultra sonography by MAKULA & Colleagues.

Main advantage of USG is its Non invasive procedure and cost effective imaging modality.

Disadvantage is its No ability for quantification of function and observe variability.

Limited visibility for deeper portions of gland. And provide no morphologic information.


V. RADIO NUCLIOTIDE SALIVARY IMAGING OR SCINTIGRAPHY

It is the dynamic and minimally invasive diagnostic test to asses salivary gland function and to determine any abnormalities in gland uptake and excretion.

This is the only test which provides information on the functional capabilities of gland.

Radio active Technetium (TC) 99m Pertechnetate is used for the purpose which is a pure gamma ray emitting nucleotide that is taken up by the glands following intravenous injections; it is transported through glands and then secreted into oral cavity.

Uptake and secretion phases can be recognized on scans. Uptake indicates that there is functional epithelial tissue.


Tc99m is capable of substituting for chloride in the Na/ K transport pump and serves as measurement of fluid movement in the salivary acinar cells.

The injected 10 to 20 mci of Tc99m is viewed in the gland by a gamma detector that records both the number and the location of gamma particles released in a given field during the period of time, this information is stored in a computer for later analysis or recorded directly on a film from gamma camera to give static image.

Scintigraphy can provide information regarding salivary gland function by generating Time – activity curves which has normally 3 phases.


Phase 1:FLOW PHASE lasts about 15 to 20 sec, Represents the phase immediately followed by injection when the isotope is equilibrating in the blood and accumulating in the gland at a sub maximal rate.

Phase 2: CONCENTRATION PHASE: Represents accumulation of Tc99m in the gland through active

transport. This starts about 1 minute after administration of tracer and

increases over next 10 minutes. Approximately after 15 minutes the tracer begins to increase in

oral cavity and decrease in the gland.


Phase 3:EXCRETORY PHASE: Other wise called wash out phase. The patient is given a lemon

drop or citric acid is applied on tongue to stimulate salivary secretion.

Normally clearing of Tc99 should be prompt, uniform, and symmetrical.

Activity remaining in gland after stimulation is suggestive of obstruction, tumor or inflammation.

The scintigraphy is used mainly to rule out auto immune

siladenitis and tumors. Basic advantage of this procedure is quantification of function and major disadvantage is of radiation hazard and also provides no morphologic information.


VI. COMPUTED TOMOGRAPHY (CT) C T images are produced by radiographic beams that

penetrate tissues. Computerized analysis of the variance of absorption produces a reconstructed image of the area.

Coronal and axial images are usually obtained.

C T is useful for evaluating salivary gland pathology, adjacent structures and proximity of lesions to the facial nerve.

Calcified structures are better visualized by CT, abscess have a characteristic hyper vascular walls is evident on CT imaging.


CT images are obtained by continuous fine cuts through involved gland. Dental restorations or metal implants may interfere with CT imaging and may require repositioning of the patient to a semi axial position.

Ultra fast and 3D CT sialography have been reported by SZOLAR and colleagues as an effective method for masses that are not well defined by MRI.

Main advantage is it differentiates osseous structures from soft tissues. And has a dis advantage of having No quantification, contrast dye injection and radiation exposure.


VII. MAGENETIC RESONANCE IMAGING (MRI) Varying water content of tissues allows for M R I to distinguish tissue

types.

A tissue absorbs and reemits the EM energy when exposed to strong magnetic field. Analysis of the net magnetization by radiofrequency is reconstructed to provide an image.

Images are described as T1 or T2 weighted images, according to the rate of constant with which magnetic polarization or relaxation occurs.

M R I is the choice of imaging in pre operative evaluation of salivary gland tumors because of its excellent ability to differentiate soft tissues and its ability to provide multiplanner images.


M R I is preferred imaging technique because needs No contrast media. Patients are not exposed to radiation and minimal artifacts from dental restorations.

M R I is contraindicated in patients with Pacemakers or metallic implant prosthesis such as bone clips

Patients with claustrophobia and pts who have difficulty maintaining still position have difficulty tolerating the

M R I procedure.


VIII. OPEN BIOPSY

Discrete salivary gland mass:

On no account should this be subjected to incisional biopsy, unless there is clear or cytological evidence of malignancy. Incisional biopsy as a primary investigation will cause tumor implantation.

Diffuse enlargement of the salivary gland:

an incisional biopsy may be necessary, but this should usually be accompanied by a sublabial biopsy, to diagnose some of the granulomatous conditions, such as sjogren’s syndrome


METHODS OF FACIAL NERVE IDENTIFICAION

1. Tragal pointer.

2. Posterior belly of diagastric.

3. Tympanomastoid suture.

4. Peripheral branches.

5. Mastoid process.


TECHNIQUE OF SALIVARY GLAND OPERATIONS

Superficial parotidectomy.

Total conservative parotidectomy.

Total radical parotidectomy.

Extended radical parotidectomy.

Neck dissection.

Removal of a submandibular gland.


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