Congenital fibrosarcoma masquerading as lymphatic malformation: report of two cases.

Two infants presented with a congenital cervicothoracic mass; both were initially diagnosed as having lymphatic malformation. A biopsy specimen for one child and excision for the other showed that both lesions were congenital fibrosarcomas. Postoperative chemotherapy was administered to both children. One died within 6 months of incisional biopsy from widespread metastatic disease; the other is still being treated. Congenital fibrosarcoma can be confused in its clinical presentation, radiographic findings, and histopathology with lymphatic malformation (cystic hygroma).