Metastatic Carcinoma Ex Pleomorphic Adenoma of Parotid Gland

Abstract

Pleomorphic adenoma is a mixed tumour   commonly involving major salivary glands. 25 of pleomorphic adenomas can undergo malignant transformation if untreated, even though they are benign tumors. There are three distinct entities in the spectrum of malignancy in pleomorphic    adenomas which include Carcinoma ex pleomorphic    adenoma, carcinosarcoma and benign metastasising  pleomorphic adenoma. CXPA is defined as the   carcinomatous transformation within a benign mixed tumour in which the initial benign elements are still identifiable .They develop from epithelial components of pleomorphic adenoma which display aggressive behaviour. Distant metastases have been reported to occur in as many as 44 of patients with CXPA which include the lungs (the most common site), pleura, pharynx, kidney, ocular choroid, liver, bone, brain, and spinal cord. None of the published literature has reported synchronous brain and lung metastasis at presentation.We report an interesting case of CXPA with upfront multiple brain and lung metastasis and review the literature of this   aggressive tumor.