Idiopathic Middle Meningeal Arteriovenous Fistula Associated with Segmental Arterial Mediolysis: A Case Report

Objective: Middle meningeal arteriovenous fistula (MMAVF) is typically post-traumatic or iatrogenic in origin, but it can have an idiopathic origin in rare cases. Here, we report a case of idiopathic MMAVF complicated by segmental arterial mediolysis (SAM).Case Presentation: The patient was a 63-year-old woman admitted to our hospital with symptoms of right pulsating tinnitus for the past 2 months. She had no significant medical history. MRI and DSA revealed a right MMAVF. Selective embolization using coils was performed. Seven years later, when she underwent laparotomy for intestinal perforation, multiple aneurysms were found in the abdominal cavity. Left hemicolectomy was performed, and an aneurysm of the gastroepiploic artery was resected. Based on a pathological examination of the aneurysm, the patient was diagnosed with SAM. Coil embolization was performed to prevent rupture.Conclusion: This case report shows that MMAVF may be associated with SAM. Fistula embolization with coils is an effective treatment of MMAVF associated with SAM. Therefore, it is important to check for systemic diseases, such as SAM when idiopathic MMAVF is detected.