Pedunculated fibrosarcoma. Unusual presentation of an intraabdominal fibrosarcoma arising from the greater omentum.

A 50 year old man presented with lower abdominal pain and hypotension of sudden onset. Emergency laparotomy for a suspected ruptured abdominal aortic aneurysm revealed the source of hemorrhage to be a ruptured vessel in the vascular pedicle of a large, oval tumor. This tumor had a unique appearance, lying virtually free within the abdominal cavity except for a 17 cm long umbilical cord-like vascular attachment to the greater omentum and a single fibrous adhesion to the anterior abdominal wall. Histologic examination disclosed the features of fibrosarcoma with a prominent population of myofibroblasts. Review of the literature yielded no previous examples of a similar pedunculated fibrosarcoma.