Carcinoma ex-pleomorphic adenoma of the parotid gland consisting of high-grade salivary duct carcinoma and keratinizing squamous cell carcinoma.

Carcinoma ex-pleomorphic adenoma (CXPA) is a rare salivary gland malignancy that presents diagnostic difficulties partly because of its wide range of histologic presentations. We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks. Magnetic resonance imaging revealed an infiltrative mass in the parotid gland, and the fine-needle aspiration (FNA) biopsy result was highly suspicious for carcinoma. Subsequent excision of the tumor demonstrated a poorly differentiated epithelial neoplasm consisting of keratinizing squamous cell carcinoma (SCC) and adenocarcinoma with regions of both ductal carcinoma in situ and invasive salivary duct carcinoma (SDC). Only focal areas exhibited a benign pleomorphic adenoma component. To our knowledge, this is the first case of a CXPA that consists of both a high-grade SDC and a keratinizing SCC in the parotid gland.