Salivary gland diseases

Lec 2
Diagnosis and Management of Salivary Gland Disorders

EMBRYOLOGY, ANATOMY, AND PHYSIOLOG
The salivary glands can be divided into two groups: the minor and major glands. All salivary glands develop from the embryonic oral cavity as buds of epithelium that extend into the underlying mesenchymal tissues. The epithelial ingrowths branch to form a primitive ductal system that eventually becomes canalized to provide for drainage of salivary secretions. The minor salivary glands begin to develop around the fortieth day in utero, where- as the larger major glands begin to develop slightly earli- er, at about the thirty-fifth day in utero. At around the seventh or eighth month in utero, secretory cells called

acini begin to develop around the ductal system. The aci-nar cells of the salivary glands are classified as either serous cells, which produce a thin, watery serous secre-tion, or mucous cells, which produce a thicker, viscous mucous secretion. The minor salivary glands are well developed and functional in the newborn infant. The acini of the minor salivary glands primarily produce mucous secretions, although some are made up of serous cells, as well. The major salivary glands are paired struc-tures and are the parotid, submandibular, and sublingual glands. The parotid glands contain primarily serous acini with few mucous cells. Conversely, the sublingual glands are for the most part composed of mucous cells. The sub-mandibular glands are mixed glands, made up of approx-imately equal numbers of serous and mucous acini. Between 800 and 1000 minor salivary glands are found throughout the portions of the oral cavity that are cov-ered by mucous membranes, with a few exceptions, such as the anterior third of the hard palate, the attached gin-giva, and the dorsal surface of the anterior third of the tongue. The minor salivary glands are referred to as the labial, buccal, palatine, tonsillar (Weber s glands), retromo-lar (Carmalt s glands), and lingual glands, which are divided into three groups: (1) inferior apical (glands of Blandin Nuhn), (2) taste buds (Ebner s glands), and (3) posterior lubricating glands .
The parotid glands, the largest salivary glands, lie superficial to the posterior aspect of the masseter muscle and the ascending ramus of the mandible. Peripheral por-tions of the parotid gland extend to the mastoid process, along the anterior aspect of the sternocleidomastoid mus-cle, and around the posterior border of the mandible into the pterygomandibular space (Fig. 20-1). The major branches of the seventh cranial (facial) nerve roughly divide the parotid gland into a superficial lobe and a deep lobe while coursing anteriorly from their exit at the sty-lomastoid foramen to innervate the muscles of facial expression. Small ducts from various regions of the gland coalesce at the anterosuperior aspect of the parotid to form Stensen s duct, which is the major duct of the parotid gland. Stensen s duct is about 1 to 3 mm in diam-eter and 6 cm in length.
Occasionally, a normal anatomic variation occurs in which an accessory parotid duct may aid Stensen s duct in drainage of salivary secretions. Additionally, an acces-sory portion of the parotid gland may be present some-
where along the course of Stensen s duct. The duct runs anteriorly from the gland and is superficial to the mas-seter muscle. At the location of the anterior edge of the masseter muscle, Stensen s duct turns sharply medial and passes through the fibers of the buccinator muscle. The duct opens into the oral cavity through the buccal mucosa, usually adjacent to the maxillary first or second molar tooth. The parotid gland receives innervation from the ninth cranial (glossopharyngeal) nerve via the auric-lotemporal nerve from the otic ganglion.
The submandibular glands are located in the sub-mandibular triangle of the neck, which is formed by the anterior and posterior bellies of the digastric muscles anc the inferior border of the mandible The posterosuperior portion of the gland curves upward around the posterior border of the mylohyoid mgives rise to the major duct of the submandibular gland known as Whartoris duct. This duct passes forward along the superior surface of the mylohyoid muscle in the sub-lingual space, adjacent to the lingual nerve. The anatomic relationship is such that the lingual nerve loops under Wharton s duct, from lateral to medial, in the posterior floor of the mouth. Wharton s duct is about 5 cm in length, and the diameter of its lumen is 2 to 4 mm. Wharton s duct opens into the floor of the mouth via a punctum located close to the incisors at the most anteri-or aspect of the junction of the lingual frenum and the floor of the mouth. The punctum is a constricted portion of the duct, and it functions to limit retrograde flow of bacteria-laden oral fluids. This particularly limits those bacteria that tend to colonize around the ductal orifices.
The sublingual glands lie on the superior surface of the mylohyoid muscle, in the sublingual space, and are sepa-rated from the oral cavity by a thin layer of oral mucosa. The acinar ducts of the sublingual glands are called Bartholin s ducts and in most instances coalesce to form 8 to 20 ducts of Rivinus. These ducts of Rivinus are short and small in diameter. They either open individually directly into the anterior floor of the mouth on a crest of mucosa, known as the plica sublingualis, or they open indirectly through connections to the submandibular duct and then into the oral cavity via Wharton s duct. The sublingual and submandibular glands are innervated by the facial nerve through the submandibular ganglion via the chorda tympani nerve .
The functions of saliva are to provide lubrication for speech and mastication, to produce enzymes for diges-tion, and to produce compounds with antibacterial properties .The salivary glands produce approximately 1000 to 1500 ml of saliva per day, with the highest flow rates occurring during meals. The relative contributions of each salivary gland to total daily pro-duction varies, with the submandibular gland providing 70%, the parotid gland 25%, the sublingual gland 3% to 4%, and the minor salivary glands contributing only trace amounts of saliva .The electrolyte com-position of saliva also varies between salivary glands, with parotid gland concentrations generally higher than the submandibular gland, except for submandibular cal-cium concentration, which is approximately twice the concentration of parotid calcium.The relative viscosities of saliva vary according to gland and correspond to the percentage of mucous and serous cell; therefore the highest viscosity is in the sublingual gland, followed by the submandibular gland, and, lastly. I parotid gland, which is composed mainly of serous eel Interestingly, the daily production of saliva begins decrease gradually after the age of 20.



Daily Saliva Production by Salivary Gland
Submandibular gland 70%

Parotid gland 25%
Sublingual gland 3%-4%
Minor glands



Trace





Incidence of Radiopaque Stones
Submandibular gland 80%
Parotid gland 40%
DIAGNOSTIC MODALITIES ;
History and Clinical Examination
The most important component of diagnosis in salivary gland disorders, as with most other disease processes, is the patient history and the clinical examination. In most cases the patient will guide the doctor to the diagnosis merely by relating the events that have occurred in association with the presenting complaint. The astute clinician must perform a thorough evaluation, and, in mar instances, the diagnosis can be determined without the necessity of further diagnostic evaluation. At the very least, the clinician may be able to categorize the problem as reactive, obstructive, inflammatory, infectious, metabolic, neoplastic, developmental, or traumatic in origin and guide further diagnostic testing. Occasionally, the clinician may find it necessary to use any of several diagnostic modalities
Salivary Gland Radiology
Plain film radiographs. The primary purpose of plain films in the assessment of salivary gland disease is to identify salivary stones (calculi), although only 80% to 85% of all stones are radiopaque and therefore visible radiographically. The incidence of radiopaque stones varies, depending on the specific gland involved (Box 20-2). A mandibular occlusal film is most useful for detecting sublingual and submandibular gland calculi in the anterior floor of the mouth (Fig. 20-4, A). A “puffed cheek view,” in which the patient forcibly blows the cheek laterally to distend the soft tissues overlying the lateral ramus, can demonstrate parotid stones. Panoramic radiographs can reveal stones in the parotid gland a posteriorly located s ubmandibular stones

Periapical radiographs can show calculi in each salivary gland or duct, including minor salivary glands, depending on film placement. In most instances, the radiographic image corresponds in size and shape to the actual stone
Siatography. The gold standard in diagnostic salivary gland radiology may be the sialogram. Sialography is indicated as an aid in the detection of radiopaque stones. In addition, when 15% to 20% of stones are radiolucent; sialography is also useful in the assessment of the extent of destruction of the salivary duct or gland or both as a result of obstructive, inflammatory, traumatic, and neo-plastic diseases. In addition to its diagnostic role, sialog-raphy may be used as a therapeutic maneuver, because the ductal system is dilated during the study, and small mucous plugs or necrotic debris may be cleared during injection of contrast.
Sialography is a technique in which the salivary duct is cannulated with a plastic or metal catheter a radiographic contrast medium is injected into the duc-tal system and the substance of the gland, and a series of radiographs are obtained during this process. Approxi-mately 0.5 to 1 ml of contrast material can be injected into the duct and gland before the patient begins to expe-rience pain. The two types of contrast media available for sialographic studies are water-soluble and oil-based. Both types of contrast material contain relatively high concen-trations (25% to 40%) of iodine . Most clinicians prefer to use water-soluble media, which are more mistible with salivary secretions, more easily injected into the finer portions of the ductal system, and more readily eliminat-ed from the gland after the study is completed, either by drainage through the duct or systemic absorption from the gland and excretion through the kidneys. The oil-based media are more viscous and require a higher injec-tion pressure to visualize the finer ductules than do the water-soluble media. As a result, they usually produce more discomfort to the patient during injection. Oil-based media are poorly eliminated from the ductal sys-tem and may cause iatrogenic ductal obstruction.
Residual oil-based contrast medium is not absorbed by the gland and may produce severe foreign-body reactions and glandular necrosis. Additionally, if the patient has duc-tal disruption secondary to chronic inflammatory changes, the extravasation of oil-based media may cause significant-ly more soft tissue damage than water-soluble material.
A complete sialogram consists of three distinct phases, depending on the time at which the radiograph is obtained after injection of the contrast material:

1. Ductal phase which occurs almost immediately after injection of contrast material and allows visualization of the major ducts
2. Acinar phase which begins after the ductal system has become fully opacified with con trast and the gland parenchyma becomes filled subsequently
3. Evacuation phase, which assesses normal secretory clearance function of the gland to determine whether any evidence of retention of contrast remains in the gland or ductal system after the sialogram



Siaiogram of right submandibular gland. Obstruction of duct by a radiolucent sialolith (arrows) has caused dilation of the duct and loss of normal parenchyma of the gland.

Siaiogram of right parotid gland. The characteristic "sausage link" appearance of the duct is demonstrated, which indicates ductal damage from obstructive disease with irregu-lar narrowing of duct caused by reparative fibrosis
The retention of contrast in the gland or ductal system beyond 5 minutes is considered abnormal. A normal siaiogram shows a large primary duct branching gradually and smoothly into secondary and terminal ductules. Evenly distributed contrast will result in opacification of the acinoparenchyma that will outline the gland and its lobules. When a stone obstructs a salivary duct, contin-ued secretion by the gland produces distension of the ductal system proximal to the obstruction and finally
leads to pressure atrophy of the parenchyma of the gland Sialodochitis is a dilation of the salivary duct secondary to epithelial atrophy as a result of repeated inflammatory or infectious processes, with irregular narrowing caused by reparative fibrosis (i.e., "sausage link" pattern) . Sialadenitis represents inflammation mainly involving the acinoparenchyma of the gland. Patients with sialadenitis experience sacculardilation of the acini of the gland secondary to acinar atrophy and infection, which results in "pruning" of the normal arborization of the small ductal system of the gland. Centrally located lesions or tumors that occupy a part of the gland or impinge on its surface displace the normal ductal anato-my. On sialography, ducts adjacent to the lesion are curvilinearly draped and stretched around the mass, pro-ducing a characteristic "ball-In-hand" appearance
Sialograms are specialized radiologic studies performed by oral and maxillofacial surgeons and some interven-tional radiologists trained in the technique. Those inex-perienced in its performance or its proper interpretation should not attempt this examination. The three con-traindications to performing a sialogram are (1) acute sali-vary gland infections, because a disrupted ductal epithe-lium may allow extravasation of contrast into the soft tissues and cause severe pain and possibly a foreign-body reaction; (2) patients with a history of iodine sensitivity, especially a severe allergic reaction after a previous radio-logic examination using contrast; and (3) before a thyroid gland study, because retained iodine in the salivary gland or ducts may interfere with the thyroid scan.
Computed tomography, magnetic resonance imag-ing, and ultrasound. The use of computed tomography (CT) has been generally reserved for the assessment of mass lesions of the salivary glands. Although CT scan-ning results in radiation exposure to patients, it is less invasive than sialography and does not require the use of contrast material. Additionally, CT scanning can demon-strate salivary gland calculi, especially submandibular stones that are located posteriorly in the duct, at the hilum of the gland, or in the substance of the gland itself.

Magnetic resonance imaging (MRI) is superior to CT scanning in delineating the soft tissue detail of salivary gland lesions, specifically tumors, with no radia-tion exposure to the patient or the necessity of contrast enhancement.
Ultrasonography is a relatively simple, noninvasive imaging modality, with poor detail resolution. The primary role of ultrasonography is in the assessment of superficial structures to determine whether a mass lesion that is being evaluated is solid or cystic (fluid-filled) in nature.
Salivary scintigraphy (radioactive isotope scanning). The use of nuclear imaging in the form of radioactive iso-tope scanning, or salivary scintigraphy, allows a thorough evaluation of the salivary gland parenchyma, with respect to the presence of mass lesions and the function of the gland itself. This study uses a radioactive isotope (usually, technetium [Tc] 99m) injected intravenously (IV), which is distributed throughout the body and taken up by a variety of tissues, including the salivary glands. The major limitation of this study, aside from patient radiation exposure, is the poor resolution of the images obtained. Salivary gland scintigraphy may demonstrate increased uptake of radioactive isotope in an acutely inflamed gland or decreased uptake in a chronically inflamed gland, as well as the presence of a mass lesion, either benign or malignant.
Salivary Gland Endoscopy (Sialoendoscopy) ;
Minimally invasive modalities of diagnosis and treatment have recently been applied to the major salivary glands. Salivary gland endoscopy (sialoendoscopy) is a special-ized procedure that uses a small video camera (endo-scope) with a light at the end of a flexible cannula, which is introduced into the ductal orifice. The endoscope can be used diagnostically and therapeuticaUy. Salivary gland endoscopy has demonstrated strictures and kinks in the ductal system, as well as mucous plugs and calcifications. The endoscope may be used to dilate small strictures and flush clear small mucous plugs in the salivary gland ducts. Specialized devices such as small balloon catheters (similar to those used for coronary angioplasty proce-dures) may be used to dilate sites of ductal constriction, and small metal baskets may be used to retrieve stones in the ductal system.
Sialochemistry ;
An examination of the electrolyte composition of the saliva of each gland may indicate a vari-ety of salivary gland disorders. Principally the concentra-tions of sodium and potassium, which normally change with salivary flow rate, are measured. Certain changes in the relative concentrations of these electrolytes are seen in specific salivary gland diseases. For example, an elevat-ed sodium concentration with a decreased potassium concentration may indicate an inflammatory sialadenitis.
Fine-Needle Aspiration Biopsy ;
The use of fine-needle aspiration biopsy in the diagnosis of salivary gland tumors has been well documented. This procedure has a high accuracy rate for distinguishing between benign and malignant lesions in superficial locations. Fine-needle aspiration biopsy is performed using syringe with a 20-gauge or smaller needle. After loc anesthesia the needle is advanced into the mass lesion the plunger is activated to create a vacuum in the syringe and the needle is moved back and forth throughout the mass, with pressure maintained on the plunger. The pressure is then released, the needle is withdrawn, and fluid cellular material and fluid is expelled onto a slide and fixed for histologic examination. This allows an immediate determination of benign versus malignant disease also offers the possibility of providing a tissue diagnosis especially if the oral surgeon and oral pathologist are experienced in performing and interpreting this examination and its results.
OBSTRUCTIVE SALIVARY GLAND DISEASE
Sialolithiasis
The formation of stones, or calculi, may occur through out the body, including the gallbladder, urinary tract, salivary glands. The occurrence of salivary gland stones is twice as common in men, with a peak incidence between ages 30 and 50. Multiple stone formation occurs approximately 25% of patients. The pathogenesis salivary calculi progresses through a series of stages beginning with an abnormality in calcium metabolism an t precipitation, with formation of a nidus that subsequently becomes layered with organic and inorganic material to form a calcified mass.
The incidence of stone formation varies, depending the specific gland involved (Box 20-3). The submadi- bular gland is involved in 85% of cases, which is more common than all other glands combined. A variety of contribute to the higher incidence of submandibular calculi. Salivary gland secretions contain water, electrolytes, urea, ammonia, glucose, fats, proteins, and other stances; in general, parotid secretions are more concentrated than those of the other salivary glands. T exception is the concentration of calcium, which is about twice as abundant in submandibular saliva as in parotid.
Sialolithiasis for the General Dentist
Classic signs and symptoms of sialolithiasis
l Exacerbation of pain and swelling at mealtimes
I Check for flow from Wharton s duct
J Check for tenderness of submandibular gland
I Palpate for stone in floor of mouth
£ Check mandibular occlusal radiograph
Treatment
Anterior stone
Attempt to dilate Wharton s duct with lacrimal probes Careful to not dislodge stone posteriorly "Milk" the gland to express stone
I If successful, prescribe salivary stimulants
Posterior stone or no stone visualized
? Refer to oral surgeon
MUCOUS RETENTI N AND EXTRAVASATION

biting, and severed beneath the surface mucosa. Subse-quent saliva production may then extravasate beneath the surface mucosa into the soft tissues. Over time, secretions accumulate within the tissues and produce a pseudocyst
PHENOMENA Mucocele Salivary ducts, especially those of the minor salivary glands, are occasionally traumatized, commonly by lip ( ithelial lining) that contains thick, vis without a true ep saliva. Te lower li after surgical remocous hese lesions are most common in the mucosa of th p and are known as mucoceles The second most common site of mucocele formation is the buccal mucosa. Mucocele formation results in an ele-vated, thinned, stretched overlying mucosa that appears as a vesicle filled with a clear or blue-gray mucus. The patient frequently relates a history of the lesion filling with fluid, rupture of the fluid collection, and refilling of these lesions. Many instances of mucocele formation regress spontaneously without surgery. For persistent or recurrent lesions, the preferred treatment consists of exci-sion of the mucocele and the associated minor salivary glands that contributed to its formation . Usu-ally, local anesthesia is administered via a mental nerve block, and an incision is made through the mucosa. Care-ful dissection around the mucocele may permit its com-plete removal; however, in many cases the thin lining rup-tures and decompresses the mucocele before removal. The regional associated minor salivary glands are removed as well and sent for histopathologic evaluation. The recur-rence rates of mucoceles may be as high as 15% to 30% val, possibly caused by incomplete removal or repeat trauma to the minor salivary glands.
RANULA:Th e most common lesion of the sublingual gland is the ranula, which may be considered a mucocele of the sub-lingual salivary gland. The two types of ranulas are the simple ranula and the plunging ranula. Ranulas result from either mucous reten tion in the sublingual gland ous extravasation as a result of duc-emergency. The differential diagnm osis of a floor of
ductal system or muc tal disruption. The simple ranula is confined to the area occupied by the sublingual gland in the sublingual space, superior to the mylohyoid muscle. The progression to a plunging ranula occurs when the lesion extends beyond the level of the mylohyoid muscle into the submandibular space. Ranulas may reach a larger size than mucoceles, because their overlying mucosa is thicker and because trauma that would cause their rupture is less likely in the floor of the mouth. As a result a plung-ing ranula has the potential to extend into the neck and compromise the airway, resulting in a medical outh swelling includes ranula, lymphoepithelial cyst, epidermoid or dermoid cyst, salivary gland tumors mucoepidermoid carcinoma), and mesenchymal tumors. (e.g., lipoma, neurofibroma, hemangioma). The dirf tial diagnosis of a midline neck mass includes thyroid enlargement (i.e., goiter or tumor), thyroglossal duct cyst, dermoid cyst, and plunging ranula. The differentia diagnosis of a lateral neck mass includes lymphadenopathy, epidermoid cyst, lipoma, infectious mononucleosis, metastatic carcinoma, lymphoma, salivary gland tumors

NECROTIZING SIALOMETAPLASIA necrotizing sialometaplasia is a reactive, nonneoplastic flammatory process that usually affects the minor salivary ands of the palate. However, it may involve minor salivary ands in any location. Necrotizing sialometaplasia is of clear origin but is thought to be secondary to vascular farction of the salivary gland lobules. Potential causes of diminished blood flow to the affected area include trauma, cal anesthetic injection, smoking, diabetes mellitus, scular disease . The usual age range of affected patients is between 23 and 66 years.



SJOGREN S SYNDROME SS is a multisystem disease process with a variable pre-sentation. The two types of SS are (1) primary SS, or sicca syndrome, characterized by xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes); and (2) secondary SS, which is composed of primary SS and an associated
connective tissue disorder, most commonly rheumatoid arthritis. Although the cause of SS is unknown, there appears to be a strong autoimmune influence. SS shows a female predilection of 9:1, with over 80% of affected individuals being females with a mean age of 50 years. Generally, the first symptoms to appear are arthritic complaints, followed by ocular symptoms, and, late in the disease process, salivary gland symptoms. The
involvement of the salivary and lacrimal glands results from a lymphocytic replacement of the normal glandular elements. The xerostomia results from a decreased function of both the major and minor salivary glands, with the parotid gland being the most sensitive. The diagnosis of SS is suggested by the patient s complaints and by a variety of abnormal immunologic laboratory tests. The oral component of SS may be diagnosed using salivary flow rate studies and sialography, but the use of a labial minor salivary gland biopsy (see Fig. 20-13) currently is considered to be highly accurate in aiding the diagnosis. The histopathologic changes seen in the minor glands are similar to those in the major glands (parotid). Keratoconjunctivitis
sicca is suggested by the patient s complaints and a
Schirmer s test for lacrimal flow . The treatment for SS includes symptomatic care with artificial tears for the dry eyes and salivary substitutes for the dry mouth. Additionally, the medication pilocarpine (Sala-gen) or the Biotene products may be useful to stimulate salivary flow from the remaining functional salivary gland tissue

TRAUMATIC SALIVARY GLAND INJURIES Traumatic injuries, particularly lacerations, involving the salivary glands and their ducts may accompany a variety of facial injuries, including fractures. Injuries that occur in close p
rroximity to one of the major salivary glands or ducts
equire careful evaluation.

Location of Tumor Occurance Major glands 80%-85% Parotid gland 85%-90% Submandibular gland 5%-10% Sublingual giand Rare Minor glands 15%-20% Palate 55% Lips 15% Remainder Rare

NEOPLASTtC SALIVARY GLAND DISORDERS;; Although a comprehensive discussion of salivary gland neoplasms is beyond the scope of this chapter and many other sources are available for this information, a brief review of several important aspects of the more common lesions is warranted. Salivary gland
posed to the minor glands {15% to 20%) Additionally, between 75% and 80% of major gland tumors are benign, whereas 50% to 55% of minor gland tumors are benign. The overwhelming majority of sail- tumors occur much more commonly in the major glands (80% to 85%), as opposed to the minor glands.

Benign Salivary Gland Tumors; The pleomorphic adenoma, or benign mixed tumor, is the most common salivary gland tumor. The mean age of occurrence is 45 years, with a male-to-female ratio of 3:2. In the major glands, the parotid gland is involved in over 80% of cas palate . Pleomorphic adenomas are usu
growing, painless masses. The histopathology shows two cell types: (1) the ductal epithelial cell and (2) the myoepithelial cell, which may differentiate along a variety of cell lines (pleomorphic means many forms). A connective tissue capsule exists, which may be incomplete. The treatment nvolves complete sur- gical excision with a margin of normal uninvolved tissue. Parotid lesions are treated with removal of the involved lobe along with the tumor. Recurrence is possible in rare occasions, as well as a small risk (5%) of malignant trans-formation to a carcinoma ex pleomorphic adenoma.

Warthin s tumor, or papillary cystadenoma lymphoma tosum, almost exclusively affects the parotid gland, specifically the tail of the parotid gland . The peak incidence is in the sixth decade of life, with a male-to-female ratio of 7:1. This lesion presents as a slow-growing, soft, painless mass. Warthin s tumor is believed to be caused by entrapped salivary epithelial rests within developing lymph nodes. The histopathology shows an epithelial component in a papillary pattern and a lymphoid component with germinal centers. The treatment of this lesion is simple surgical excision, and recurrence is rare. The monomorphic adenoma is an uncommon solitary lesion composed of one cell type, affecting predominantly the upper lip minor glands (canalicular adenoma) (Fig. 20- 28) and the parotid gland (basal cell adenoma). The mean age of occurrence is 61 years, and the lesion usually presents as an asymptomatic, freely movable mass. The histopathology reveals an encapsulated lesion composed of one type (monomorphic) of salivary ductal epithelial cell. The treatment is simple surgical excision.

Malignant Salivary Gland Tumors The mucoepidermoid carcinoma is the most common malignant salivary gland tumor. It comprises 10% of ma rs (mostly parotid) and 20% jor gland tumo of minor gland tumors (mostly palate) . This
lesion may occur at any age, but the mean age is 45 years. T ratio is 3:2. The entation is a the male-to-female clinical presubmucosal mass tnful or ulc ass may app tinge bec ucous conte hin the traosseous form of mu carcinoma a multilocular radio rio postehe histopathologl typ ells, (2) epide ermediate ( he pro helps t nterm
ade l moe r epidermoidm, la s hat may be pai erated. The m ear to have a bluish ause of the m nt contained wit lesion. An in coepidermoid may present
as lucency of the r mandible. T y shows three cel es: (1) mucous c rmoid cells, and (3) int clear) cells. T portion of each cell type o grade the mucoepidermoid carcinoma as high-, i ediate-, or lowgr esions. The higher the grade, the predominance of cells and pleo-morphis ck of mucous cells and cystic areas, and overall more aggressive behavior. The treatment of low-grade lesions is wide surgical excision with a margin of uninvolved normal tissue; high-grade lesions require more aggressive surgical removal with
margins, and, possibly, local radiation therapy. The low- grade lesions have a 95% 5-year survival rate, whereas the high-grade lesions have less than a 40% 5-year survival rate.The polymorphous low-grade adenocarcinoma is the second most common intraoral salivary gland malignancy. This lesion was first described in 1983; before its identification, many cases were probably misdiagnosed as adenoid cystic carcinoma. The most common site is the junction of the hard and soft palates . The male-to-female ratio is 3:1, with a mean age of 56 years.

Written by :
Mushtag T. mohammed
4th stage.