Hemangiopericytoma arising in the greater omentum: report of a case.

Although hemangiopericytoma may arise in any anatomic site, it rarely develops in the greater omentum. To our knowledge, only ten cases have been reported to date in the English-language literature. We report herein an additional case of hemangiopericytoma arising in the greater omentum. A review of the reported cases suggests that surgical resection provides the only chance of cure and that a high mitotic index (>4/10 high-power fields) and a tumor size of > or =20 cm predict an unfavorable prognosis after resection.