Epithelial myoepithelial carcinoma of the parotid gland with malignant ductaland myoepithelial components arising in a pleomorphic adenoma: a case report with cytologic,histologic and immunohistochemical correlation
BACKGROUND: To describe the cytologic, histologic and immunohistochemicalfindings of a case of epithelial myoepithelial carcinoma (EMC) arising from a pleomorphic adenoma(PA) of the parotid with both malignant epithelial and myoepithelial components. CASE: A 29-year-oldfemale presented with a 1.5 x 1.5-cm, palpable mass of the left parotid of 7-8 months’ durationwith recent enlargement and pain. Fine needle aspiration biopsy (FNAB) revealed biphasic epithelial(small cell) and myoepithelial (large/clear cell) clusters arranged in a pseudopapillary andtrabecular pattern with abundant hyaline material with many naked nuclei, together with areastypical of pleomorphic adenoma (PA) was noted. The cytology was reported as salivary gland neoplasm,”suggestive of adenoid cystic carcinoma, less likely pleomorphic adenoma.” The mass was excised andhistologically reported as “pleomorphic adenoma, with focal invasion of one resected margin.” Fourmonths later the tumor recurred, and FNAB showed almost the same cytologic features as did theprevious aspirate. Due to early recurrence, previous histologic sections were reviewed, and typicalareas of a biphasic pattern of EMC with atypicality and mitosis of both components was found. Thefinal diagnosis was EMC ex PA. CONCLUSION: Although previous reports mention the difficulties indiagnosing EMC and differentiation from the more common salivary gland neoplasms such as PA, we liketo emphasize the cytologic confusion that results when the tumors coexist.
Daneshbod,Y　Negahban,S　Khademi,B　Daneshbod,K
Department of Cytopathology, Dr. Daneshbod Pathology Laboratory, ShirazMedical School, Shiraz, Iran. daneshbk@yahoo.com
Adenoma, Pleomorphic　 Adult　 Carcinoma　 Cell Nucleus　 Epithelial CellsFemale
