title: Low grade mucoepidermoid carcinoma ex pleomorphic adenoma. A diagnostic problem in fine needle aspiration biopsy.
abstract: We report a case of low grade mucoepidermoid carcinoma arising in a pleomorphic adenoma (ex pleomorphic adenoma) in the parotid salivary gland of a 32-year-old woman. Fine needle aspiration biopsy showed the typical biphasic pattern of pleomorphic adenoma: groups of benign-appearing epithelial cells and chondromyxoid stroma. In addition, features of low grade mucoepidermoid carcinoma were identified retrospectively, consisting of background mucin and rare mucin-containing cells. This case illustrates that the presence of background mucin and mucin-containing cells in an otherwise usual pleomorphic adenoma may indicate the presence of a well-differentiated mucoepidermoid carcinoma. In cases such as this, a definitive diagnosis should be postponed until the lesion is examined histologically.
authors.affiliation: Laboratory Department, Naval Hospital, Oakland, California 94627-5000.
authors.forename: J C
authors.initials: JC
authors.lastname: Jacobs
mesh_terms: D008949:Adenoma, Pleomorphic / Q000737:chemistry / Q000473:pathology*; D000328:Adult; D001707:Biopsy, Needle; D018277:Carcinoma, Mucoepidermoid / Q000737:chemistry / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D009077:Mucins / Q000032:analysis; D009378:Neoplasms, Multiple Primary / Q000737:chemistry / Q000473:pathology*; D010307:Parotid Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D009077:Mucins