Bilateral acinous cell tumors of the parotid gland

Acinous cell tumors are uncommon neoplasms which arise either from the secretory cells of the salivary gland acini or from pluripotential duct cells and occur almost exclusively in the parotid gland. Nine previous instances of the bilateral occurrence of this tumor in the parotid gland have been reported. We present a tenth case and illustrate several aspects of the clinical behavior of this unique tumor. The histological pattern of this type of tumor was considered universally to be benign until 1953 when attention was called to a malignant variant. It is difficult to find reference to a benign form after that time. It is, in fact, impossible to forecast the clinical behavior of an individual specimen based upon its histopathology. In order to recognize this unpredictability, the World Health Organization Classification of Epithelial Tumors of Salivary Gland Origin proposed a category, "Acinic Cell Tumors," separate from clearly benign or malignant neoplasms. Later, attention was called to the grammatical designation, "acinous cell tumor." Because acinous cell tumors are uncommon, numerically significant series are gathered from several institutions or over several decades during which treatment methods vary widely. This makes it difficult to accept the validity of conclusions based upon the reported data. There is, however, a clearly documented tendency of the tumor to recur after long symptomless intervals so that extended follow-up is necessary before "cure" is established. Treatment of acinous cell tumors is surgical. The value of radiation therapy in the management of recurrent tumors is not firmly established.