ABSTRACT
Carcinosarcoma ex pleomorphic adenoma of the salivary gland is an extremely rare tumor of themajor and minor salivary glands that is composed of a mixture of both carcinomatous and sarcomatouselements with an identifiable benign epithelial and mesenchymal tumor counterpart.This report describes a rare case of carcinosarcoma ex pleomorphic adenoma involving the left parotidgland in a 61-year-old female with no history of a long-standing pleomorphic adenoma, nor a recurrentpleomorphic adenoma, and describes its morphology and important immunohistochemistry findings.Carcinosarcoma ex pleomorphic adenoma contains features of the two tumors under malignant mixedtumors, which are carcinosarcoma and carcinoma ex pleomorphic adenoma. Immunohistochemistrystudies were done to document the epithelial and mesenchymal areas from both the malignant andbenign sections of the tumor and to classify the carcinoma and sarcoma component, consisting ofadenocarcinoma, not otherwise specified for the carcinoma component, and myxoid chondrosarcomaand mesenchymal chondrosarcoma for the sarcoma component.The paucity of documented cases of carcinosarcoma ex pleomorphic adenoma in prior scientificpublications requires reporting cases such as this. Furthermore, the report provides an insight intothe more complex molecular and structural changes that manifest as cancer behavior in the tumorsof the salivary gland. The case contributes to the fund of knowledge for diagnosis and improvementof quality of care.