Superior mesenteric artery branch aneurysm with spontaneous hemoperitoneum.

A 70-year-old man without any particular medical history or past trauma was referred to our hospital with a complaint of intermittent epigastric pain lasting for 1 day. On admission, his vital signs were stable, and he exhibited diffuse abdominal tenderness without distention, rebound or guarding. Except for a decreased level of hemoglobin at 105 g/L, all the laboratory values were within the normal ranges. Abdominal computed tomography (CT) revealed the presence of an ill-demarcated hyperdense mass inseparable from the small bowel mesentery(Picture A). Contrast-enhanced CT revealed a mesenteric hematoma accompanying with a mesenteric branch artery aneurysm (Picture B-D). As the patient was hemodynamically stable, his family refused surgery and embolization. His symptoms subsided with conservative