Diagnostic challenges in cytology of mucoepidermoid carcinoma: Report of 6 cases with histopathological correlation

Background: Mucoepidermoid carcinoma (MEC) is a malignant salivary gland neoplasm with extreme morphologic heterogeneity and hence rendering a definitive fine needle aspiration cytology (FNAC) diagnosis of this neoplasm is really challenging. The present study was undertaken to elucidate the cytological features of MEC and explore the diagnostic accuracy and pitfalls by comparing with subsequent histopathology. Materials and Methods: The present study was conducted over a period of 2 years wherein we obtained six histopathologically confirmed cases of MEC. These patients were initially subjected to FNAC. The cytologic features studied included presence of mucous cells, intermediate cells, and squamous cells. Presence of background mucinous material was also noted. The cytological features were compared with the subsequent histopathology. Results: Of the 6 cases of MEC, a definite cytological diagnosis was possible only in 2 cases. Of the remaining 4 cases, 2 cases were broadly diagnosed in cytology as neoplasm with cystic degeneration and 2 cases were underdiagnosed as pleomorphic adenoma. Conclusions: A satisfactory aspirate with all three types of cells; mucous, intermediate and squamous cells may not be obtained in all cases of MEC for providing a definite diagnosis. Hence, a good clinicoradiological correlation, a high index of suspicion and repeated aspirations especially in cystic lesions may be particularly helpful in difficult cases. In addition, while dealing with mucinous cystic lesions with low cellularity, the importance of early excision should be communicated to the clinician since the possibility of low-grade MEC cannot be excluded.