Merkel cell tumor of the thigh.

This case of a Merkel cell carcinoma is unusual due to the occurrence of the tumor on the thigh; most Merkel cell tumors have been found on the sun-exposed region of the head and neck. Histologically, the nodule was composed of sheets of uniform, poorly differentiated cells with a high nuclear to cytoplasmic ratio. Electron microscopy revealed perinuclear filaments, scattered dense core granules, and complex, interdigitating processes within cytoplasmic membranes. Treatment consisted of surgical excision of the tumor with a wide margin.