Merkel cell carcinoma with bone metastasis: a case report.

A case of Merkel cell carcinoma with bone metastasis is described. The patient, who had a history of Merkel cell carcinoma of the skin in the right cheek, had spontaneous pain in the right thigh. At the initial visit, the right hip range of motion was slightly limited, but there was no gait disturbance or abnormality in the radiographs of the right hip. However, the pain gradually increased and caused gait disturbance. The patient underwent surgical treatment. A bipolar type of femoral prosthesis was implanted into the femur, and sampling of cancellous bone was performed at the time of osteotomy. Pathological examination showed the findings of Merkel cell carcinoma. Merkel cell carcinoma is a rare malignant tumor of the skin, which usually occurs on the head, neck, or extremities and metastasizes to the lymph nodes. Although osseous involvement often occurs in the adjacent facial bones through direct invasion, distant osseous metastasis appears to be extremely rare.