[Congenital Fibrosarcoma of the Left Index Finger - An Unusual Case].

Congenital fibrosarcoma is a rare mesenchymal soft tissue tumour, which most commonly develops in the peripheral extremities during infancy. Diagnostic work-up is a challenge for clinicians and pathologists alike, because in many cases the lesion initially resembles a haemangioma on macroscopic inspection. A 4-month-old boy presented with a strongly vascularised tumour of the left index finger, which had been diagnosed as a capillary haemangioma by means of a biopsy performed in another facility. The lesion had been treated with systemic and intralesional cortisone injections. Due to ulceration and the risk of infection, the tumour mass was resected with the index finger being preserved. The histological appearance was inconclusive. PCR revealed a congenital fibrosarcoma. 2 years after surgery, the boy is free from recurrence.