Extraskeletal Osteosarcoma of the Omentum with Aggressive Development.

For the first time extraskeletal osteosarcomas (ESOS) were described by Wilson in 1941. They are extremely rare neoplasms, presenting 4% of all osteosarcomas and 1,2% of all soft-tissue sarcomas. About 300 cases have been reported in the literature up to date. We present a 66-year-old female patient, admitted in the clinic because of acute bleeding in retroperitoneal space. Revision of the retroperitoneal space and haemostasis were performed. The patient was re-operated because postoperative bowel obstruction. The reason for it was intestinal infiltration from large tumor of the omentum, determined histopathologically as ESOS. The case was considered as an unresectable neoplasm so a colostomy was performed. In the literature we found 3 case reports of ESOS, originated from omentum.