Abstract
A 33-year-old man suffered sudden abdominal distension without traumatic episodes. He had undergone total splenectomy for hereditary spherocytosis 13 years ago. He was in shock, and his hemoglobin level was 10.5 g/dl. Contrast enhanced computed tomography revealed a giant mass in the left upper abdomen and extravasation of the contrast material into the mass. Excision of the mass was performed, and microscopic examination showed a giant hematoma surrounded by normal splenic tissue. We speculated that an accessory spleen or splenosis had enlarged for the 13 years and ruptured. The patient remained asymptomatic 4 months after the surgery. Spontaneous hemorrhage from accessory spleens or splenosis is extremely rare, and relevant case reports suggest that surgical resection of bleeding sites yields favorable prognosis although preoperative qualitative diagnosis seems to be difficult.