[Parapharyngeal oncocytoma of the parotid gland]

Oncocytic tumors rarely occur in major salivary glands and generally account for less than 1% of all salivary tumors. Oncocytomas are infrequent tumors that most commonly arise in the salivary, thyroid, parathyroid and pituitary glands, kidneys and pancreas. They are rarely malignant. Oncocytic differentiation may also occur focally in a benign or a malignant epithelial tumor, such as a thyroid adenoma, papillary cystadenoma lymphomatosum and mixed tumors of salivary glands, malignant carcinoids of the bronchus, adrenal cortical carcinoma, and renal cell carcinoma. The term oncocytoma refers to a single neoplasm contrast to nodular oncocytic hyperplasia, which refers to two or more distinct tumor nodules, and to oncocytic mucoepidermoid carcinomas, where there is evidence of infiltrative growth and malignant of clinical behavior. We here report surgical treatment and light and electron microscopical findings obtained in the case of an oncocytoma of the parapharyngeal prestyloid space in a 62-year-old man who was admitted to our Department because of a slowly enlarging, painless mass in the pharyngeal extension of the right parotid gland. The mass has distorted the isthmus of the fauces, compressing the contra lateral pharyngeal-palatal plica. A total right parotidectomy which spared the branches of the facial nerve was performed. During the operative procedure, tissue was removed for frozen-section examination. The patient had an uneventful post-operative course. For all that has previously been written about oncocytic tumors, relatively very little is known of their etiology. In the past a correlation was made between the etiology and the history of direct or indirect radiation exposure. As oncocytic metaplasia and oncocytomas are often seen most in older individuals, the oncocyte was previously regarded as a "functional exhaustion" of a normal cell. As far as we concerned, the preferred method of surgically exposing the parapharyngeal-prestyloid space is that of removing the parotid gland through a cervical approach. Because of the proximity of certain anatomical structures, the transoral approach is not the most suitable.