Congenital primary cutaneous rhabdomyosarcoma in a neonate.

We report a case of congenital primary cutaneous rhabdomyosarcoma, solid alveolar type, presenting as a solitary skin lesion on the right upper lip of a 2-week-old infant boy. Rhabdomyosarcoma originates from the embryonic mesenchyme precursor of striated muscle. Histologically it belongs to the group of "small round cell tumors." Its myogenic origin is ascertained by immunohistochemical studies positive for myogenin, muscle-specific actin, desmin, and myoglobin. Malignancy in the neonatal period is uncommon and the clinical management presents considerable challenges. Congenital alveolar rhabdomyosarcoma is a highly malignant tumor with no record of long-term survivors. Treatment options include chemotherapy, excision, and radiotherapy. This infant's tumor was responsive to chemotherapy and surgery and he was free of disease at the 6-month follow-up.