F-18 fluorodeoxyglucose positron emission tomographic imaging: in search of an unknown primary tumor.

Epithelioid sarcoma is a rare tumor that occurs almost exclusively in the distal extremities. The primary site in this case was seen with F-18 fluorodeoxygluclose (FDG) positron emission tomography (PET). This tumor exhibits various histologic growth patterns and diverse clinical presentations, and thus the diagnosis is often delayed for months or years. They have a tendency to spread to noncontiguous areas of skin, subcutaneous tissue, fat, and bone. Many case reports have suggested a causal relation to trauma. Treatment includes wide surgical excision, often involving amputation of the extremity, and regional lymph node dissection.