Oncocytic Carcinoma Ex Pleomorphic Adenoma

Abstract

Carcinoma ex pleomorphic adenoma (CaexPA) is a carcinoma that shows histologic evidence of arising in a pleomorphic adenoma. The diagnosis is made on identification of benign tumor or carcinoma arising in a site previously involved by pleomorphic adenoma. Most often the carcinomatous element is adenocarcinoma, not otherwise specified (NOS), but occasionally a specific histologic type, such as salivary duct carcinoma, mucoepidermoid carcinoma, adenoid cystic carcinoma can be identified [1–5]. Onococytic carcinoma (OC) is a rare, predominantly oncocytic neoplasm. The terms OC and oncocytic adenocarcinoma are synonymous. Malignant oncocytic tumors can occur in many organs such as thyroid, kidney, ovary, nasal cavity etc. as well as in salivary glands. The oncocytic nature of the tumor cells is confirmed with special methods, such as histochemical or immunohistochemical stains [2]. OC’s rarity is highlighted by the absence of this tumor in many large salivary gland neoplasm series [4, 6–11]. Here we present the first reported case of CaexPA with purely oncocytic carcinomatous elements.