Segmental arterial mediolysis of varying phases affecting both the intra-abdominal and intracranial vertebral arteries: an autopsy case report.

We report an autopsy case of segmental arterial mediolysis (SAM) of various phases occurring in both the intracranial vertebral artery (IVA) and intra-abdominal arteries. The patient was a 70-year-old male found dead in his house. The cause of death was massive intra-abdominal hemorrhage owing to a ruptured right gastroepiploic artery. Histopathological examination revealed that there was a broad arterial dissection as long as 20 cm in the right gastroepiploic artery associated with SAM in the injurious phase. In addition, SAM in the reparative phase was observed as organized arterial dissections in the left gastric artery. Furthermore, SAM in the reparative phase was detected as an arterial dissection in the right IVA undergoing an organizing process. These three lesions were considered to have developed at different times. SAM occurring in both the intra-abdominal and intracranial vertebral arteries is extremely rare. This coincidence may provide a clue to the relationship between SAM and spontaneous IVA dissection.