Fatal hemoperitoneum due to segmental arterial mediolysis.

Spontaneous hemoperitoneum due to vascular injury is a life-threatening condition mostly associated with aortic or splanchnic arterial disease, which stems from atherosclerotic, inflammatory, or infectious origin. However, in 1976, Slavin and Gonzales described a nonatherosclerotic arterial disease that may render aneurysmal formation predominantly in the splanchnic arterial bed. The clinical presentation is diverse, but abdominal pain and shock prevail. We report the case of a middle-aged man who presented a hemoperitoneum due to a middle colic artery aneurysm rupture and died after undergoing a surgical treatment attempt. The preoperative imaging study revealed the presence of a huge hematoma in the epiplon retrocavity, and abdominal free liquid as well as extensive arterial disease with multiple aneurysms. The autopsy findings included hemoperitoneum, hematoma in the upper left abdominal quadrant, the surgical ligature of the middle colic artery, and histologic features consistent with segmental arterial mediolysis. The authors call attention to this rare entity and highlight the autopsy as a fundamental examination to accurately reach this diagnosis.