Congenital fibrosarcoma of the upper extremity.

Congenital or infantile fibrosarcoma is a rare soft-tissue neoplasm that should be considered in the differential diagnosis of a large extremity mass presenting at birth. These tumors are notoriously misdiagnosed at birth as either hemangiomas or lymphatic malformations. Definitive diagnosis is made by physical examination, special radiologic studies, and biopsy. Although histologically similar to fibrosarcomas occurring in adults, the congenital lesions differ in their clinical behavior; metastases are rare, local recurrence is common, and the prognosis is good with wide local excision combined with chemotherapy. Amputation should be reserved for chemoresistant patients in whom the involvement of neurovascular structures by the tumor make a limb-sparing aggressive excision impossible.