Carcinosarcoma of the Parotid

Abstract

Carcinosarcoma of the parotid is a rare biphasic malignant neoplasm comprised of both carcinomatous and sarcomatous components representing approximately 0.4% of all malignant salivary gland neoplasms. We report a case of a 55-year-old Caucasian man who presented with a progressively enlarging left facial mass. Histopathological evaluation of the tumoral tissue revealed a high grade, mixed epithelial and mesenchymal malignant tumor, most consistent with a carcinosarcoma of the parotid. Morphoproteomic analysis was performed and revealed expression of secreted protein acidic and rich in cysteine (SPARC); glioma-associated oncogen protein 2 (Gli2); and phosphorylated signal transducer and activator of transcription (p-STAT3 [Tyr705]) in the carcinomatous and malignant mesenchymal components. These aforementioned markers have been linked to the epithelial–mesenchymal transition in which epithelial cells lose their characteristics and phenotypically become mesenchymal cells. This finding allows us to further understand the biology of the 2 cellular components of the carcinosarcoma as having a monoclonal origin.