CLASSIFICATION OF PAROTID GLAND

TUMOURSPLEOMORPHIC ADENOMA

ANATOMYPara- around

otis-ear

Largest salivary gland

Parts – superficial (80%) , deep (20%)

Duct – Stensen’s

HISTOLOGY

FACIAL NERVE

FACIOVENOUS PLANE OF PATEY

BLOOD SUPPLY: External carotid artery

VENOUS DRAINAGE : External jugular vein

LYMPHATIC DRAINAGE : Deep cervical nodes

One subtype, Membranous BCA- Appears hereditary.Often occurs in combination with skin appendage tumors- Dermal

Cylindromas & Trichoepitheliomas.Multiple bilateral tumors- Because these tumors often bear a

histopathologic resemblance to the skin tumors- Dermal analogue tumors.

Gross pathology:

Round to ovoid, well-circumscribed, with smooth surface capsule, firm in consistency- similar to lymph node.

Membranous Basal cell adenoma- Multinodular.Cut surface- homogenous, solid appearance that may be

interrupted by cysts of varying sizes, filled with brown/ red mucinous or blood, gray white to pink red or brown in color.

(a)Clinical examination: Small nodule behind the left ear. (b)basaloid cells in nests sheets and trabeculae (PAP stain; ×100). (c) peripheral palisading of cells (red arrows) and bare nuclei in

background (PAP, x400)); (d) basement membrane material around cell clusters (green arrows) (PAP,

x400

Trabecular type :

Narrow epithelial islands forming an interconnecting cord-like architecture- reticular pattern.

Tubular type.

Prominent multiple duct-like structures with intraluminal eosinophilic secretion occurs in conjugation with trabecular pattern to form a trabeculotubular patternLeast common

Inner cuboidal ductal cellsOuter layer of basaloid cells

2 cells

A number of salivary gland tumors can be characterized

microscopically by a papillomatous pattern.

The sialadenoma papilliferum, intraductal papilloma , and

inverted ductal papilloma are three rare salivary tumors

that also show unique papillomatous features.

viral - human papillomavirus

DUCTAL PAPILLOMAS (SIALADENOMA PAPILUFERUM; INTRADUCTAL PAPILLOMA; INVERTED DUCTAL PAPILLOMA)

Histopathologic Features

Sialadenoma papilliferum is somewhat similar to the squamous

papilloma , exhibiting multiple exophytic papillary projections that are

covered by parakeratotic stratified squamous epithelium.

This epithelium is contiguous with a proliferation of papillomatous

ductal epithelium found below the surface and extending downward into

the deeper connective tissues.

Sialadenoma papilliferum demonstrating the typical exophytic papillary surface and deeper ductal components.

Gross pathology:Varies from discrete encapsulated nodule to lesions that

are circumscribed but encapsulated.Sometimes multifocalPink-tan to tan, brown or yellowSometimes cystic spaces with gelatinous material seen

Mucous cells- vary in shape, abundant pale foamy cytoplasm that stains positive for mucin stains.

- relatively large, may assume round, cuboidal, ovoid, columnar or goblet shapes.

- stains positive for mucicarmine and PAS stain.Epidermoid cells- squamous features, polygonal shape.Intermediate cells- larger than basal cell, smaller than

squamous cell. Proginitor of epidermoid and squamous cells.

Clear cells- larger, polygonal and defined cytoplasmic borders.

Mucus cells - mucicarmine stain,

Clear cells - PAS

Tubular pattern:Tubular structure that are lined by stratified cuboidal

epithelium.Longitudinal section- ductal structures are viewed as ducts or

tubules.Lumina contains mucinous substance- PAS positiveCribriform pattern may exist with tubular pattern.

Adenoid cystic carcinoma.

Tubular variant showing morphologically clear abluminal cells.

Solid pattern:Solid groups of cuboidal cells with little

tendency towards ducts or cyst formation.Arranged in nests or sheets of varying size

and shape.Areas of necrosis seenCellular pleomorphism, mitosis observed.

Adenoid cystic carcinoma.

Solid variant higher power showing scattered duct-like structures within the tumor sheet.

Adenoid cystic carcinoma. The tumor cells aresurrounded by hyalinized material

Adenoid cystic carcinoma. Perineural invasion.

Dedifferentiation of adenoid cystic carcinoma- Recently defined, rare varient.- characterized histologically by 2 component1. Conventional low grade adenoid cystic carcinoma2. high grade dedifferentiated carcinoma. Because of frequent recurrence and matastasis, the

clinical course is short, similar to AdCC with a predominant solid growth pattern.

Histologically low grade AdCC merges gradually into extensive dedifferentiated component that is composed of solid sheets and cords of anaplastic tumor cell with focal gland formation..

p53 gene alteration plays a pivotal role.

Varients

Epithelial myoepithelial carcinoma (EMEC) is a rare low-grade malignant salivary gland neoplasm.

less than 1% of all salivary gland neoplasms.ORIGIN: intercalated ductA malignant tumor composed of variable proportions of two

cell types, which typically form duct-like structures.The biphasic morphology is represented by an- Inner layer of darker cells, that represent intercalated duct

epithelial component- Outer layer of clear, myoepithelial-type cells.

EPITHELIAL MYOEPITHELIAL CARCINOMA

Higher magnification showing luminal intercalated Duct like cells and abluminal clear cells.

Differential diagnosis:Pleomorphic adenomaClear cell tumorsClear cell oncocytomaMyoepithelial carcinomaClear cell myoepitheliomaMucoepidermoid carcinomaMalanoma Adenoid cystic carcinoma

Recently recognized type of salivary malignancy that was first

described in 1983.

Evans and Batsakis first used the term

PLGA occurs almost exclusively in the minor salivary glands

Characterized by: Bland, uniform nuclear feature, diverse by

characteristic architecture, infiltrative growth and perineural

invasion.

POLYMORPHOUS LOW-GRADE ADENOCARCINOMA

(LOBULAR CARCINOMA; TERMINAL DUCT CARCINOMA)

Gross pathology:Firm, circumscribed, but non-encapsulated, yellow tan

lobulated nodule, average size 2.2cms.Bony invasion may be seem in large lesion in the hard patate,

may impinge upon the maxillary bone and cause bone resorption and laterally medullary invasion

Gross image shows bone invasion in a large tumor in the hard palate

Histopathologic features:

Characterized by: Infiltrative growth with diverse morphology

& Uniform nuclear appearance

At low power, the tumor sometimes appears well circumscribed.

peripheral cells are usually infiltrative, invading the adjacent

tissue in a single- file fashion.

Difference growth pattern- hence the name polymorphous.

Variety of growth patterns- solid, ductal, cystic, tubular or

cribriform

Tumor stroma- varies from mucid to hyaline and in some areas

separated by fibrovascular stroma.

In some tumors, a cribriform pattern can be produced that

mimics adenoid cystic carcinoma .

Mitotic figures are uncommon.

Perineural invasion common.

CLASSIFICATION OF PAROTID GLAND TUMOURS

EPITHELIAL( 90%)

NONEPITHELIAL HemangiomaLymphangiomaNeurofibroma

• MALIGNANT LYMPHOMA – NHL TYPE

EPITHELIAL (90%)BENIGN (ADENOMAS)

Pleomorphic adenomaMonomorphic adenoma

Warthin’s tumour (adenolymhoma)Oncocytoma ( oxyphil adenoma )Basal cell adenoma

EPITHELIAL ( 90% )MALIGNANT

LOW GRADE Acinic cell

carcinomaAdenoid cystic

carcinomaLow grade

mucoepidermoid carcinoma

• HIGH GRADE• Adenocarcinoma

• Squamous cell carcinoma

• High grade mucoepidermoid carcinoma

CASEA 45 yr old femaleC/0 – slow growing, painless

swelling below the left side of ear for the past 5 months

O/e – 5x3 cm,oval, lifting the ear lobule

No localised warmth, not tender Surface-smooth, Margins- well

defined. Retromand groove oblit. Variable consistency. Mobile Not adherent to skin, masseter

muscle No signs suggestive of facial N inv Examination of oral cavity is normal

FNAC : shows ductal cells, chondromyxoid matrix and myoepithelial cells

DIAGNOSIS : PLEOMORPHIC ADENOMA

PLEOMORPHIC ADENOMAMIXED TUMOUR

SITE : MC: PAROTID GLAND ( 90%)- MC –Tail of gland

Submandibular gland (7%) Minor salivary glands-MC : Palate

Occurs more commonly in females (3:1) AGE : any age . MC : 40-50yrs Usually unilateral

PATHOLOGYBENIGN TUMORTumor capsule-well formed, but incompleteTiny excrescences (pseudopods) project

outside.Give rise to recurrences.

GROSS :CUT SECTION:

MICROSCOPIC APPEARANCE2 groups of cells :Well differentiated

epithelial cells-acini/cords/sheets

Spindle/stellate cells Abundant intercellular

mucoid material-resembles cartilage

Pleomorphic stromaNo necrosisRarity of mitotic figures

CLINICAL FEATURES Painless slow growing swellingIn the parotid both lobes involved. If only deep

lobe involved – DUMB BELL TUMOURDysphagia if deep lobe is involvedDeviation of uvula&pharyngeal wall towards

midline-deepDeep lobe swelling passes through PATEY’S STYLOMANDIBULAR TUNNELRaised ear lobuleCannot be moved abv zygomatic bone-CURTAIN

SIGNFACIAL NERVE NOT INVOLVED

INVESTIGATIONFNAC – IMPORTANT AND DIAGNOSTIC

OPEN BIOPSY – CONTRAINDICATEDDUE TO : chance of injury to facial nerve,seedling & high chance of recurrence,Parotid fistula formation

CT SCAN

MRI

MANAGEMENTTumor is RADIO RESISTANTSURGERY :ENUCLEATION –avoided. High recurrence.TOC : SUPERFICIAL PAROTIDECTOMY – PATEY’S OPERATION( if supf lobe alone involved)

TOTAL CONSERVATIVE PAROTIDECTOMY (If both lobes involved)FACIAL NERVE IS PRESERVED

COMPLICATIONSRECURRENCE ( 1 – 5 %)

MALIGNANCY3-5 % IN EARLY TUMORS10% IN LONG DURATION( >15

YRS)

RECURRENCE AFTER SURGERYDUE TO : SpillageInadequate marginRetained pseudopodsMulticentricityImproper technique

Recurrent tumor is multinodular without capsule

Marker to predict recurrence : MUC1/DF3

CARCINOMA IN EX PLEOMORPHIC ADENOMALong standing Pl.adenoma-malignant

transformationRecent increase in sizePain , nodularityInvolvement of skin, ulcerationInvolvement of masseterInvolvement of facial nerveNeck lymph nodeRestriction of jaw movements

TAKE HOME MESSAGEMOST COMMON TUMOUR OF PAROTID

FACIAL NERVE IS NOT INVOLVED

TOC : SUPERFICIAL PAROTIDECTOMY

FACIAL NERVE IS PRESERVED.

CARCINOMA IN EX PLEOMORPHIC ADENOMA.