Omental Hemangiosarcoma in Five Dogs

Five dogs were diagnosed with omental hemangiosarcoma (HSA). Three of the dogs were Schnauzers. One dog was asymptomatic and four dogs presented with urinary or colonic obstruction. Computed tomography, performed in three cases, revealed a well-circumscribed caudal abdominal mass that displaced local abdominal organs. Surgical exploration confirmed that the masses were associated with the omentum. The mass was removed in four cases and debulked in one. Histopathologic evaluation in all cases was consistent with HSA. One dog underwent adjuvant chemotherapy and survived 170 days, whilst adjuvant chemotherapy was declined in the other cases, with survival times ranging from 50-120 days. Omental HSA can result in clinical signs related to fecal or urinary obstruction due to the size of the mass and caudal location within the abdomen. Although omental HSA is a rare anatomic variant of HSA, it does behave similar to splenic and other visceral HSA, with a guarded prognosis.