Minimally invasive carcinosarcoma ex pleomorphic adenoma: A case report and literature review with cytohistological correlation.

BACKGROUND Carcinosarcoma of the salivary glands is a rare neoplasm, and the minimally invasive form constitutes a subgroup with a more favorable prognosis. The cytomorphologic features of this neoplasm can be appreciated on fine-needle aspiration biopsy. METHODS AND RESULTS We present a patient with a minimally invasive carcinosarcoma ex non-recurrent pleomorphic adenoma (Ca ex PA) who underwent initial fine-needle aspiration biopsy followed by surgical resection. The tumor was composed predominantly of a light microscopic pleomorphic high-grade sarcoma exhibiting partial myoepithelial immunohistochemical features, with a minor component of in situ and invasive salivary duct carcinoma (10%). A limited area with features of a hyalinized pleomorphic adenoma was identified. CONCLUSION This is the third case report of the cytological features of Ca ex PA of the salivary gland, with histologic correlation. It further illustrates the oncogenic relationship between epithelial and myoepithelial elements in the early stages of carcinosarcomatous transformation. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2483-E2489, 2016.