Introduction on cytology of Salivary gland Prepared by

Mr. Lin Wai Fung (MSc, MPH, CMIAC)

Normal salivary gland (Note: ductal cells and acinar cells, “bunch of grapes” clusters)

Non-neoplastic lesions

Granulomatous inflammation (note: epitheloid cells, F/67, submandibular gland)

Cystic changes F/36 (Note: foam cells)

Haemorrhagic cystic lesion M/72

Chronic inflammation (note: atrophy of acini and proliferation of ducts) M/55, submandibular gland

Retention cyst (note: many foamy histocytes) M/30 Submandibular gland

Branchial cyst F/16 Right parotid mass Note: a lot of degenerated epithelial cells

Benign Salivary Gland Neoplasms

Benign Salivary Gland Neoplasms • Benign neoplasms are the majority of salivary gland tumors accounting for 85% parotid, 63% submandibular, 14% sublingual glands • Common: pleomorphic adenoma, Warthin Tumour • Rare: myepithelioma, oncocytoma, sebaceous adenoma, cystadenoma, and papillomas

Pleomorphic adenoma • May recur especially for incomplete resection • common in parotid • Cytology – epthelial cells + myoepithelial cell component – Stromal component: myxoid, chondroid, chondromyxoid, hyaline, – gradual transistion of epithelial/myoepithelial component into stromal component: “melting” – myoepthelial cells: plasmacytoid hyaline cells, spindly/ovoid naked nuclei

Pleomorphic adenoma F/34 Parotid gland (right) (note: loose clusters of plasmacytoid myoepithelial cells and the chondromyxoid stroma) Plasmacytoid myoepithelial cells

Epithelial / myoepthelial melting

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Warthin’s tumor • Only in parotid gland • Two main component – reactive lymphoid cells in background – Papillary structures lined by double layers of uniform oncocytic epithelial cells, may have distinct nucleoli, fine chromatin

Warthin‘s tumor M/88 FNA left parotid mass •

Oncocytic cells

Cell block

Monomorphic adenoma (basal cell adenoma) • Morphologically similar to Pleomorphic adenoma but no “melting” or stromal component • Numerous cell clusters with few dissociated cells • Regular round or oval nuclei and sparse cytoplasm • Bland, granular nuclear chromatin • Variable amounts of stromal material probably of basement membrane origin

Monomorphic adenoma (basal cell adenoma) M/52, FNA left parotid

Monomorphic adenoma (basal cell adenoma) F/54 , FNA left parotid

Cell Block

Section

Malignant Neoplasms

Adenoid cystic carcinoma • Most common primary salivary gland malignancy • Biphasic cells population: epithelial (usually basaloid) and myoepithelial cells • Basement membrane material and hyaline globules • Cribriform, cylindromatous pattern • Other pattern: sheets, branching clusters, Pseudoglandular / microcystic • Nuclear atypia: cells usually small, uniform and hyperchromatic, chromatin pattern: fine to coarse

Adenoid cystic carcinoma F/69 FNA left submandibular mass

Mucoepidermal carcinoma • Cell types: epithelial cells – Mucinous epithelial cells – Intermediate epithelial cells – Squamous epithelial cells

• High grade: more squamous cells, more nuclear atypia • Low grade: more mucinous cells, mild nuclear atypia • Lower grade tumor often cystic, low celluarity, and commonly with inflamed background. Distinction from benign cystic condition may be difficult

Mucoepidermal carcinoma, low to intermediate grade, F/68, Left parotid lesion

Vacuoles ↓

MC stain

Mucoepidermoid carcinoma, high grade M/77 FNA left parotid mass

Vacuole

Acinic cell carcinoma • Usually cellular aspirate • Cell types: Epithelial cells only, no myoepithelial cells • Serous acinic cells: basophilic or amorphilic with granular cytoplasm, without ducts • Other cell types: clear cells, mucinous cells, intercalated cells • Architectural patterns: solid sheets, papillary structures, microcystic / follicles • Proportion of cells types and pattern vary

Acinic cell carcinoma M/20 Right Parotid gland

PASD

Epthelial-myoepthelial carcinoma • • • • • • •

Epithelial-myoepithelial carcinoma (EMEC) of the salivary glands was described by Donath et al in 1972 (1). It is a rare tumor, accounting for less than 1% of all salivary gland neoplasms, most commonly in the parotid gland female predominance peak occurrence in the seventh decade EMEC is a low-grade malignant tumor that may commonly recur locally after resection. Distant metastasis rarely occurs Consists of both an epithelial and myoepithelial component

Epthelial-myoepthelial carcinoma F/48 FNA left floor of mouth mass

Other neoplasms

Leiomysarcoma F/68 Parotid gland

Vimentin positive

Schwannoma F/66 Submandibular gland

Malignant lymphoma (B cell type) F/43 Parotid gland

Metastatic squamous cell carcinoma F/61 Parotid gland

Multiple Myeloma M/71 Parotid gland

Adenocarcinoma F/56 Parotid gland

Undifferentiated carcinoma M/60 Parotid gland Known case of NPC

Reference • Mukunyadzi P (2002) Review of Fine-Needle Aspiration Cytology of Salivary Gland Neoplasms, with Emphasis on Differential Diagnosis, Am J Clin Pathol : 118 (Suppl1): S100-S115 • Manual and Altas of Fine Needle Aspiration Cytology, Orel SR et al (ed), 3rd edition