Epidermal cyst with ossification: a patient report.

Epidermal cysts are common skin tumors that are composed of a cyst wall of epidermal cells and central keratin material. They rarely show ossification. A 68-year-old man was referred to our clinic for evaluation of multiple cysts on his left forehead, left cheek and right shoulder. Histopathological examination revealed that all of the cysts were epidermal cysts, and focal ossification was observed outside the cyst on the forehead. We speculated that chronic inflammation caused ossification around the cyst. Therefore, epidermal cyst should be included in the differential diagnosis of cysts with ossification.