Mucoepidermoid carcinoma ex pleomorphic adenoma: nonspecific preoperative cytologic findings in six cases

In contrast to most major salivary gland malignancies, mucoepidermoid carcinoma has been rarely documented and tentatively accepted as carcinoma ex pleomorphic adenoma. The authors present the cytologic and clinical findings for six examples of these rare tumors.

The six examples were identified during an extensive review of the authors' salivary gland files, and all were high grade mucoepidermoid carcinomas on histologic evaluation.

Overall, mucoepidermoid carcinomas cytologically presented as non-specific high grade malignancies and consisted of highly malignant cells, in clusters or isolated, that were rarely associated with intracellular and extracellular mucin. In only two cases, a background of cellular and stromal elements consistent with pleomorphic adenoma was identified.

Although it is nearly impossible cytologically to distinguish these lesions from other high grade primary or metastatic carcinomas (such as poorly differentiated squamous cell carcinomas, adenosquamous carcinomas, and salivary duct carcinomas), this limitation is not dramatic, as a cytologic diagnosis of high grade malignancy per se allows for proper preoperative patient management.