You answered: Low-grade mucoepidermoid carcinoma
Sorry, that is INCORRECT
The correct diagnosis is: Acinic cell carcinoma
- The aspirate is highly cellular consisting of numerous epithelial clusters in a lymphoid background. The epithelial groups contain monomorphic cells with delicate vacuolated cytoplasm, bland nuclei with variable prominent nucleoli and only minimal atypia
- The clusters are crowded and disorganized, and single neoplastic cells can be found
- These features are most suggestive of an acinic cell carcinoma
- The biopsy reveals a well-circumscribed tumour with prominent acinic cell differentiation admixed with intermediate sized cells with less abundant granular cytoplasm.
- Acinic cell carcinoma is an uncommon neoplasm of the salivary glands that most often involves the parotid gland.
- Aspirates from a well-differentiated acinic cell carcinoma may resemble normal salivary gland acini; however they are usually highly cellular with variably sized cell sheets and lack the discrete, round, organized acini of normal salivary gland tissue. Individual cells of an acinic cell carcinoma are larger and often more variable than normal acinar cells and single neoplastic cells and bare nuclei can often be found in the background. Unlike normal gland tissue ductal epithelium is not present with neoplastic cells. With careful examination some cells may reveal small metachromatic granules with Giemsa stains or DPAS positive granules on alcohol fixed smears or cellblock material.
- Aspirates from low-grade mucoepidermoid carcinoma may contain cells with clear, vacuolated cytoplasm and bland nuclei, however cells with squamoid appearance and background mucus are usually present. Naked nuclei are uncommon. The cells will lack cytoplasmic granules.
- The intense lymphocytic reaction seen in some acinic cell carcinomas, particularly if the cells have more dense cytoplasm, may suggest Warthin’s tumour or other oncocytic tumours. However, high cellularity, the presence of vacuolated cytoplasm and single naked nuclei favours acinic cell carcinoma. The cells will lack cytoplasmic granules.
- Aspirates from chronic sialadenitis may contain reactive lymphoid tissue but usually have only few small fragments of duct epithelium with a lack of acinar epithelium.
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Orell SR, Sterrett GF, Whitaker D. Fine Needle Aspiration Cytology, 4th ed. Elsevier Churchill Livingstone; 2005. pp65-67.
Ramzy I. Clinical Cytopathology and Aspiration Biopsy, 2nd ed. McGraw-Hill Medical Publishing Division; 2001. pp403-4.
Demay, Richard M. The Art & Science of Cytopathology: Chicago: ASCP Press, 1996. pp679-80