Giant Retroperitoneal Hemangiopericytoma with Paraneoplastic Gynecomastia

We report on a 38-year-old patient with a giant retroperitoneal hemangiopericytoma associated with bilateral paraneoplastic gynecomastia, which led to an almost uncontrollable hemorrhage on initial surgery due to the extreme hypervascularity of the process. After angiographic evaluation and superselective embolization, a complete surgical excision of a hemangiopericytoma weighing almost 1,000 g could be achieved. To reduce the risk of recurrence adjuvant radiotherapy with 49 Gy followed. Follow-up of 24 months showed no sign of recurrence on CT scans. To our knowledge this is the first reported case of hemangiopericytoma associated with a paraneoplastic syndrome. The literature and the therapeutic concepts are presented and discussed.