Basal Cell Adenoma Arising from the Accessory Parotid Gland: A Case Report and Review of the Japanese Literature

Abstract

Basal cell adenoma is a rare benign salivary gland tumor. The majority of the cases arise in the main parotid gland. In this paper, we report a case of basal cell adenoma in the right accessory parotid gland. The patient was a 70-year-old female with a 30×30 mm, elastic-firm, subcutaneous tumor in the right mid-cheek region. Magnetic resonance imaging showed that the tumor was located above the masseter muscle anterior to the main parotid gland. Surgical resection was performed under local anesthesia. Histopathologically, the tumor was composed of solid, trabecular, and duct-like structures. Solid and trabecular structures were constituted of small isomorphic cells with hyperchromatic, round nuclei. The diagnosis of basal cell adenoma of the accessory parotid gland was established from these clinicopathological findings. We reviewed the recent Japanese literature and found that the development of basal cell adenoma in the accessory parotid gland is exceedingly rare and that the incidence of malignancy in accessory parotid gland tumors is higher than that previously reported in the parotid gland tumors.