Mucoepidermoid carcinoma of the parotid presenting as periauricular cystic nodules: a series of four cases.

Mucoepidermoid carcinoma is a relatively common neoplasm of the major and minor salivary glands that can secondarily involve skin. In the vicinity of the ear lobe, mimicry of a benign cyst, both clinically and histopathologically is a diagnostic pitfall to avoid. The clinical manifestations, diagnostic histopathology, and clinical course of mucoepidermoid carcinoma of the parotid gland presenting as a clinically benign periauricular cystic nodule in four patients ranging in age from 11 to 63 years, are analyzed in the present report. Illustrating the challenge of accurate diagnosis, three of the four cases were initially misinterpreted on biopsy as benign cystic lesions. Multiple biopsies displayed foamy histiocytes around mucinous extravasations into dermis that mimicked ruptured epithelial cysts in two cases before malignancy was ascertained. This series demonstrates the need to include parotid tumor in the differential diagnosis of odd periauricular cyst-like expansions and adenosquamous proliferations. Mucoepidermoid carcinoma in particular can explain indolent, infra-auricular 'mucinous cysts'. Familiarity with this syndrome should arouse suspicion of parotid carcinoma when a 'cyst' or nodule is located near the earlobe. Delay in diagnosis results in larger surgical procedures than are otherwise necessary.