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POLYMORPHOUS LOW GRADE ADENOCARCINOMA AGE CHANGES IN SG-minor SG, mostly palate-good prognosis-unpredictable potential to metastasize in 15% cases

in weight of parotid & submandibular glands relatedto atrophy of secretory tissue & replacement byfibrofatty tissue

Similar changes in labial minor SG

Oncocyte change in ductal epithelium

in flow rate of submandibular gland

Histopathologic:-variety of growth pattern within the same lesion

Solid

Tubular Papillary

Cribriform-cytologically uniform-bland with infrequent mitoses-lack of atypia-D/D adenoid cystic carcinoma (both show perinueralinvasion)

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PLEOMORPHIC ADENOMA (MIXED TUMOR)Commonest SG tumor

:: 60-65% parotid:: 45% minor SG

7% originate in minor SG esp palatalOld ages, femaleUsually solitaryRecurrences may be multifocal

Clinicalfeatures

-Slowly growing, painless, rubbery swellingwith intact overlying skin or mucosa-pts may be aware of lesion for several yrs

Histopathologicfeatures

-compose of cells of epithelial &myoepithelial origin-great variety with complex intermingling ofcomponents & mesenchyme-like areas-although benign, CT capsule is x alwayscomplete-clearly demarcated, but apparently

isolated nodules may be seen within oreven outside the capsule, giving theimpression of invasive growth-serial sections show that these representoutgrowth of the main mass-These islands explain the need for excisionwith a margin to avoid recurrence-variation in arrangement of epithelial &stromal components btwn different tumors& within different areas of same tumors-epithelial components may be arranged in

duct-like structures sheets

clumps

interlacing strands

Duct

surrounded

by

Dilate

d

Kerati

n

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WARTHIN TUMOR(PAPILLARY CYSTADENOMA LYMPHOMATOSUM)

Mostly parotidSlow-growingMultifocalBilateral (5-10%)Old ageMostly frm residual salivary duct epithelium entrappedwithin lymp nodes during dvlpmnt

Clinical

features

Gross appearance:

-multiple, irregular cystic spaces of variable sizecontaining mucoid material-lining of cyst has small projections (papillary structures)

Histopathologicfeatures

Multiple, irregular cystic spaces containing mucoidmaterial separated by papillary projections of tumortissue

Tumor consists of:

Epithelial component: double-layered epitheliumlining cystic spaces in papillary arrangement

Lymphoid component within stroma, may containgerminal centers

Epithelial cells have granular cytoplasm rich in abnormalmitochondria, resembling oncocytes

Cyst

ic Lympho

id tissue

Double

layer of

epitheliu

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BASAL CELL ADENOMA ONCOCYTOMA CANALICULAR ADENOMA DUCTALPAPILLOMAS

-1-2% of all SG tumor-79% parotid, 20% upper lip-Peak incidence in 7th decade

-rare-usually in parotid->60 yrs of age

->50 yrs of age-almost all cases in upper lip-no clinical significance-x represent invasive growth

-rare-several subtypes

-Consist of cytologically uniform basaloidcells arranged in variety of patterns-well-encapsulated

-thin capsule-consists of oncocyte

-consists of anastomosing strands ofbasaloid epithelial cells arranged incanalicular structures-partly or grossly cystic due todegeneration of loose vascularstroma-in some cases, multiple microscopicfoci of adenomatous change seensurrounding minor SG

-papillary structureprojecting into theductal system

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MUCOEPIDERMOID CARCINOMA

10% of all SG tumors

major SG: mostly parotid

minor SG: mostly palatal

highest incidence in 4th & 5th

decade

low grade MEC 1

low grade MEC 2

Low grade MECi. Well-differentiatedii. Mucous & epidermoid cells

predominateiii. No cellular pleomorphismiv. Often cystic, cyst lined by mucous-

secreting cellsv. Epidermoid cells present in strands

or clumps, show keratinizationvi. Rupture of mucin-containing cyst

lead to inflammationvii. Advance on a broad, pushing front

low grade MEC 3

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Clinical features:

similar to pleomorphic adenoma

grossly cystic tumors may befluctuant

more aggressive tumors maycause pain & ulceration

high grade MEC 1

High grade MECi. poorly-differentiatedii. epidermoid & intermediate cells

predominateiii. nuclear & cellular pleomorphism,

atypiaiv. cystic spaces x prominentv. difficult to differentiate frm SCCvi. ill defined & highly infiltrative

Histopathologic features:3 types of cells1. Squamous (epidermoid)2. Mucous3. Intermediate

relative proportions & arrangements ofcell types are used to distinguish btwn:

High grade MEC

Low grade MEC

Prognosis-low grade tumor rarely metastasize-however, behavior cannot be accuratelypredicted frm histopathology

-overall 5-yr survival rate: 70%-low grade tumors 5-yr survival rate: 95%

Local recurrence:

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OTHERS SGCARCINOMA

ACINIC CELL CARCINOMA CARCINOMA ARISING IN PLEOMORPHIC ADENOMA

1. ADENOCARCINOMA-relatively uncommon-1% or less of all bodymalignancies-5% of head n neckmalignancies-most common in majorSG esp parotid-however! Ratio ofmalignant to benign inminor SG is higher than inmajor

*not otherwise specified(NOS)

-Uncommon-accounts for 2-3% of parotid tumors-low grade malignancy-80-100% 5-yr survival rates for well-differentiated tumors-65% 5-yr survival rates for poorly-differentiated tumors

-known as carcinoma ex pleomorphic adenoma-3% of all SG tumors-almost all arises in parotid or submandibular longstanding tumors-histological dx requires evidence of pre-existingpleomorphic adenoma-malignant component may be an:

adenocarcinoma

undifferentiated carcinoma

other types of SG carcinoma-when the malignant part is confined within pre-existingtumor, prognosis is excellent-poor prognosis when there is infiltration-some mixed tumors arise as malignant de novo

-spectrum of histopathologicalappearances-most common: sheets or an acinargrouping of large, polyhedral cells withbasophilic, granular cytoplasm (similar to

serous acinar cells) hence the name!

2. EPITHELIALMYOEPITHELIALCARCINOMA

3. BASAL CELLADENOCARCINOMA

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ADENOID CYSTIC CARCINOMA-middle-aged & elderly-30% minor SG, 6% major (parotid)

Histological features:-wide spectrum of appearance

-most common: epithelium arranged as ovoid & irregularly shaped islands, or

anastomosing cords & strands in scanty CT stroma

-numerous microscopic cyst-like spaces within epithelial islands cribriformor Swiss cheese pattern-epithelium consists of small, uniform, basophilic cells-rare mitoses-less common:

epithelium arranged in tubular or solid pattern-prominent infiltration & invasion of adjacent tissues, spread around & alongnerves-in maxilla, tumor may infiltrate along marrow spaces with no evidence ofbone destruction-perineural invasion

Clinical features:-slow enlarging tumors (like pleomorphicadenoma) but pain & ulceration are morecommon-parotid tumors present with facial palsy-neurological manifestation: infiltrate & spreadalong nerves

Prognosis:-radiotherapy used in inoperable cases, but xcure permanently-runs a prolonged clinical course & metastases

Tumo

r cell

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are late, usually to lungs-long term prognosis is poor-survival rate for parotid tumors

5-yrs: 75%

10-yrs: 40%

20-yrs: