Warthin-like Variant of Mucoepidermoid Carcinoma of the Parotid Gland

A 57-year-old woman with a 2-year history of a left infra-auricular mass with no associated symptoms presented with a 6.0 cm ´ 4.0 cm ´ 3.0 cm firm, non-tender, movable mass. No imaging was done. Fine needle aspiration biopsy (FNAB) revealed sheets of epithelial cells that had abundant dense grayish-blue cytoplasm in a mucinous background with abundant lymphocytes (Figure 1), suggestive of salivary gland neoplasm with oncocytic or oncocytoid features (Category IVB, Salivary Gland Neoplasm of Uncertain Malignant Potential).1 Total parotidectomy revealed a 4.3 X 3.2 X 3.0 cm deep lobe lesion with a tan-grey to dark brown, smooth and dull external surface. Cut sections showed a cream-white to pink, lobulated, heterogenous cut surfaces. Microscopically, the lesion was unencapsulated with poorly demarcated borders. The neoplastic cells were arranged in haphazard sheets and surrounded by abundant lymphocytes. The tumor cells had abundant eosinophilic and granular cytoplasm compatible with oncocytes with mild to moderate nuclear atypia. There were occasional cystic spaces that contained mucin though mucocytes were not readily apparent. (Figure 2) Necrosis, perineural and lymphovascular space invasion or anaplasia were not evident.