Unexpected sudden death due to a spontaneous rupture of a gastric dissecting aneurysm: an autopsy case suggesting the importance of the double-rupture phenomenon.

Gastric dissecting aneurysm is a very rare lesion with a potential risk of fatal rupture. Differentiating this from a traumatic lesion may be important in forensic casework. We report an autopsy case of sudden death due to a clinically overlooked spontaneous rupture of gastric dissecting aneurysm. A 91-year-old Japanese male visited a hospital with complaints of back pain and general fatigue, and then died at his home about 4 h later. Postmortem examination revealed massive hemoperitoneum and a subserosal hematoma originating from a vascular lesion at the lesser gastric curvature with a serosal tear. The histological findings were compatible with segmental arterial mediolysis (SAM). The pathological findings and clinical course suggested the possible 'double-rupture phenomenon' (delayed fatal rupture). This case suggested the importance of careful investigation such a vascular lesion in medico-legal practice, not only to differentiate from traumatic injury but also to investigate the process of dying.