Metastatic oncocytic adrenocortical carcinoma of mandible: an extraordinarily rare occurrence.

Adrenocortical carcinoma (ACC) is an uncommon primary cancer in the adrenal gland. Its incidence of showing metastasis in the head and neck region is very rare. Herein, we present a case of a 46-year-old man who presented with complaints of pain and numbness on the left side of the lower face for 4 months. Radiographic examination revealed an osteolytic lesion with an ill-defined border in the left body region of the mandible. Histopathologic examination revealed a tumor composed of sheets of oval to polygon-shaped tumor cells predominantly displaying abundant eosinophilic granular cytoplasm. These tumor cells showed features of a high degree of anaplasia. On immunohistochemical examination, tumor cells were focally positive for synaptophysin, inhibin, vimentin, pancytokeratin (pan-CK), cytokeratin (CK)5/6, CD68, and CK8/18 and immunonegative for CK7, chromogranin, melan-A, S100, SMA, and SATB2. The Ki-67 proliferation index was approximately 20%. To the best of our knowledge, this is the first case of metastatic oncocytic ACC to the oral cavity region.