[Carcinoma in ectopic Warthin's tumor: a case study and review of the literature]

Warthin's tumor is the second most common salivary gland tumor preceded only by pleomorphic adenoma. In most cases it involves the parotid gland and can, at times, be bilateral. It can also arise in ectopic salivary tissue in the latero-cervical and para-parotid lymph nodes. This neoplasm consists of two histologic components: one epithelial, the other lymphoid. Malignant transformation involving each of these tissues has been reported. However, few cases give clear-cut examples of the epithelial malignant change. Therefore, primary malignant transformation of Warthin's tumor is extremely rare. This event appears related to the initial time of tumor onset and/or past radiotherapy for other malignant cervico-facial lesions. The authors report a case of epidermoid carcinoma arising on an ectopic Warthin's tumor in a 57-year-old male. Physical examination revealed a recent, smooth tumor mass on the left, located near the laryngeal thyroid cartilage. Fine needle aspiration cytology was suspicious of a malignant epithelial neoplasm. Functional latero-cervical dissection, modified by excision of the digastric and sternohyoid muscles plus a 2 x 2 cm section of the overlying skin, was performed in this case. Histology and immunocytochemical tests on the surgical specimen revealed a 14 cytokeratin-positive, malignant epidermoid neoplasm arising from the adjacent 14 cytokeratin-negative, oncocytic epithelium. This relationship may rule out metastasis and may, therefore, be a case of Warthin's tumor associated with an epidermoid carcinoma or a case of branchial cyst.