Androgen receptor-positive mucoepidermoid carcinoma: case report and literature review.

Androgen receptor (AR) is usually expressed in salivary duct carcinoma (SDC), but only infrequently in other carcinoma types including mucoepidermoid carcinoma (MEC). The clinicopathological characteristics of AR-positive MEC remain to be clarified. Here we report a case of AR-positive MEC. A 76-year-old man presented with a growing painless tumor of the right parotid. The resected tumor was a high-grade tumor with necroses. Since the tumor was positive for AR, GCDFP-15, and HER2, SDC was first suspected, but it was also positive for CK5/6 and P63, and negative for S-100 protein and α-smooth muscle actin. In addition, scattered mucous secreting tumor cells were found in the tumor nests, and they were positive for Alcian blue. A diagnosis of AR-positive MEC was finally made. The patient died of the tumor 5 years after the surgery. The present case may expand the histopathological spectrum of high-grade MEC.