MAHAK RALLI, ROLL NO. 42

BENIGN TUMOURS OF SALIVARY GLANDS

PLEOMORPHIC ADENOMA

• Most common benign salivary neoplasm consisting of cells exhibiting the ability to differentiate epithelial cells (ductal and nonductal cells) mesenchyme-like cells (chondroid, myxoid or osseous)• This results in different histopathologic patterns in the

tumours. Hence the name pleo- (meaning many) morphic (meaning shape, form )

ETIOLOGY

• 60% of all salivary gland tumours • 85% of these are found in the parotid gland, 8% in

submandibular gland and the remaining in sublingual and minor salivary glands• Histogenesis –Numerous theories have been advanced.Current theory- based on myoepithelial and reverse

cells of the intercalated ducts.

CLINICAL FEATURES

• Age- 30 to 50 years• Gender- slight female predilection • Location –superficial lobe of parotid > submandiblar

gland> palate• Signs and symptoms It is a slow growing and painless massRarely ulcerates the overlying skinIn parotid gland, the tumour grows in posterior and

inferior aspect of superficial lobe measuring a few cms.

In the submandibular gland, it is a well defined palpable mass.

CLINICAL FEATURES

• When occuring in the parotid, the ear lobe of the affected side might elevate.• When observed in-situ, it is encased in

pseudocapsule and exhibits a lobulated surface.• The palatal tumours are smooth-surfaced and

dome shaped masses.

Typical appearance of pleomorphic adenoma

Removal of palatal tumour

PATHOLOGY

• Gross appearance Firm, smooth mass within a pseudocapsule• Histological appearanceHas both epithelial and mesenchymal cellsStroma consists of chondroid, myxoid, osseous and

fibroid cellsThere is presence of microscopic projections which

are necessary to remove, or they become the cause for recurrence.

Neoplastic cells are seen arranged in ductal patterns, sheets and islands. Stroma is delicately collagenous with myxoid areas.

Few cells show vacoular degenartion

Neoplastic cells are seen arranged in ductal patterns, sheets and islands. Stroma is delicately collagenous with myxoid areas.

Few cells show vacoular degenartion

DIFFERENTIAL DIAGNOSIS AND TREATMENT

• DIFFERENTIAL DIAGNOSISAdenolymphomaOncocytomaAdenocarcinoma Warthin’s tumour• TREATMENT

Surgical removal of the tumour including adequate margin

Superficial parotidectomy, if the tumour is affecting the parotid gland

Removal of the entire submandibular gland may be required if the submandibuar gland is affected

PAPILLARY CYSTADENOMA LYMPHOMATOSUM

• Also known as Warthin’s tumour.• Second most common benign tumour seen in the

parotid gland• It is characterized by proliferation of both luminal

and non-luminal cells.

CLINICAL FEATURES

• Age- 60 to 70 years• Gender- slight male predilection• Location- parotid most commonly affected, inferior

and posterior to the angle of mandible• Signs and symptoms-It is a slow growing, painless nodular massIt is firm in consistency or fluctuantIt can occur as a bilateral lesion (unique feature)It is metachronous i.e appearing at different times,

not simultaneously.Oncocytes take up technetium and is visible on Tc

99m scintiscans.

CLINICAL APPEARANCE

PATHOLOGY

• Gross appearance-Tumour is smooth and has a well defined capsule.Cut specimen shows cystic spaces filled with thick

mucinous material.• Histological appearance-Cyst formation with papillary projections in the cystic

spaces.Inner luminal cells are tall, columnar and eoisnophilic

with palisaded nuclei.Outer luminal cells are cuboidal or polygonal.There is characteristic lymphocytic infililtration.

DIFFERENTIAL DIAGNOSIS AND TREATMENT

• DIFFERENTIAL DIAGNOSISPleomorphic adenomaOncocytomaParotid lymph node enlargement

• TREATMENTSurgical excision involving a margin of normal tissueIn cases where a significant amount of superficial

lobe is affected, superficial parotidectomy is done.Recurrence and malignant changes are rare

ONCOCYTOMA

• Less common benign tumour (<1%)• The name is derived from presence of oncocytes.• These cells resemble the apparently normal cells.• Oncocytic cells are considered as somatic mutants

rather than new specific cell lineage.• Oncocytic transformation of epithelial cells is not

degenerative but rather a redifferentiation of epithelial cells which develope an increased but unbalanced metabolism.

CLINICAL FEATURES

• Age- 50 to 80 years• Gender- female predilection• Location- parotid gland most commonly affected• Signs and symptoms- Discrete, encapsulated, slow growing mass3-5cm in diameterPainless and firmDiffuse multinodular oncocytoma appears when

many nodular masses involve the entire glandCan occur bilaterallyRarely seen intraorally

Oncocytoma, clinical appearance

PATHOLOGY

• Gross appearance-Non cystic and firm• Histology-Brown, granular eosinophilic cells with central nuclei

and arranged in sheets, nests or cord.Oncocytes concentrate technetium and can be

visualized by Tc 99m scintigraphyMalignant oncocytomas can occur and are

aggressive.

DIFFERENTIAL DIAGNOSIS AND TREATMENT

• DIFFERENTIAL DIAGNOSISPleomorphic adenomaWarthins tumourParotid lymphnode enlargement• TREATMENTSuperficial parotidectomy with preservation of the

facial nerve, in parotid glandRemoval of the gland, in submandibular glandGland removal with a normal cuff of tissue is the

treatment of choice for oncocytomas of minor salivary glands

BASAL CELL ADENOMA

• It is an uncommon salivary gland tumour, histopathologically composed of basaloid (resembling basal cells), epithelial cells arranged in solid, trabecular, tubular or membranous patterns.• Hence the name basal cell adenoma• It arises from the neoplastic transformation of

reserve cells in intercalated ducts and shows differentiation of both epithelial and myoepithelial elements

CLINICAL FEATURES

• Age- 50 to 70 years• Gender- female predilection• Location- 70% in parotid, upper lip (minor salivary

gland)• Signs and symptoms-Slow growing, freely movablePainlessLess than 3cm in diameter

CLINICAL APPEARANCE

PATHOLOGY

• It is well-encapsulated tumour in major salivary glands whereas in minor salivary glands, the capsule will be ill-defined• Three varieties exist-1.Solid- islands or sheets of basaloid cells. Normal

sized- nuclei and basophilic with minimal cytoplasm.2.Trabecular-tubular form- cord of epithelium3.Membranous form- multilocular and 50% cases are

encapsulated. It grows in clusters interspersed with normal salivary gland tissue.

DIFFERENTIAL DIAGNOSIS AND TREATMENT

• DIFFERENTIAL DIAGNOSISCanalicular adenomaSebaceous adenomaClear cell adenoma• TREATMENTConservative surgical excision extending to normal

tissue. Low recurrence rate, except membranous form

maybe.

CANALICULAR ADENOMA

• Uncommon neoplasm composed of epithelial cells arranged in a single or double layer forming branching cords in a loose stroma• CLINICAL FEATURESAge- older than 50 yearsGender- female predilectionLocation- 80% cases in the upper lipSymptoms and signs- slow growing, movable and

asymptomatic. Well-circumscribed and painless.

HISTOLOGY

• Long columns or cords of cuboidal columnar cells in a single layer• These layers are parallel, form long canals• Sometimes, row of cells are loosely approximated

and appear as a double row of cells• The supporting stroma is loose, fibrillar and highly

vascular.• The cystic spaces are filled with eosinoplhilic

material.

MYOEPITHELIOMA

• Uncommon salivary gland tumour (<1%)• Occurs in the parotid gland and in minor salivary

glands of the palate.• No gender predilection.• Average age group affected is in the sixth decade

of life.• Clinically, it is a well-circumscribed, asymptomatic,

slow-growing mass.

PATHOLOGY

• Consists of spindle-shaped, plasmacytoid cells, or a combination of the two• Diagnosis is based on identification of myoepithelial

cells and must be differentiated from other benign and malignant epithelial and mesenchymal tumours for treatment planning.• Growth patterns vary from solid to a loose stroma

formation with myoepithelial cells.• This tumour is epithelial in origin however, it

functionally resembles smooth muscle and is demonstrated by immunohistochemical staining for actin cytokeratin and S-100 protein.

TREATMENT

• Standard surgical excision, including a border of normal tissue, is recommended.• Recurrence is uncommon.

SEBACEOUS ADENOMA

• A rare benign tumour derived from sebaceous glands located within salivary gland tissue• Parotid gland is most commonly involved• Age group affected – 22 to 90 years, mean age at

initial clinical presentation is 58 years.• The tumour is more common in men.• CLINICAL PRESENTATIONEncapsulated or sharply circumscribed tumour that

varies in color from grayish white to pinkish white to yellow or yellowish grey.

PATHOLOGHY AND TREATMENT

• PATHOLOGY• These are composed of sebaceous cell nests with

minimal atypia and pleomorphism and no tendency to invade• Sebaceous glands vary in size and are usually

embedded in a fibrous stroma.• TREATMENTConservative excision.No recurrences.

DUCTAL PAPILLOMA

• They include three rare benign salivary gland neoplasms which exhibit papillary projections i.e. showing surface projections, histologically.• The unique features of this tumour are-1.Papillar projections2.All three tumours arise from the excretory duct3.Commonly affects the minor salivary gland• Three benign tumours include-1.Intraductal papilloma2.Sialadenoma papilliferum3.Inverted ductal papilloma

SIALADENOMA PAPILLOMA

• CLINICAL FEATURESAge- 30 to 70 yearsMale predilectionMost commonly seen on palate and buccal

mucosa minor glands.Well-circumscribed, painless, papillary exophytic

growth

• HISTOLOGYEpithelium lined papillary projections supported by

fibrovascular connective tissue, forming a series of clefts within the lesion

INVERTED DUCTAL PAPILLOMA

• CLINICAL FEATURESAge- 30 to 60 years.Male predilectionBuccal mucosa, lower lip and vestibule of lower

jaw.Asymptomatic, firm, submucosal nodule <1.5cmOccurs near the orifice of salivary gland ducts.• HISTOLOGY• Resembles sialadenoma• Consists of projections of ductal epithelium that

proliferate to surrounding tissues, forming clefts.

TREATMENT

• Surgical excision• Recurrence is rare.