Suspected Segmental Arterial Mediolysis with Spinal Subarachnoid Hemorrhage and Mesenteric Aneurysms

Segmental arterial mediolysis (SAM) rarely involves spinal vasculature. A 63-year-old woman with muscle-invasive urothelial bladder cancer developed acute abdominal and lower back pain 2 days after cisplatin and 3 days after gemcitabine chemotherapy. CT showed a small omental infarct, and spinal MRI demonstrated extensive thoracolumbar intraspinal hemorrhage. Spinal angiography revealed a left C5 radiculomedullary aneurysm. Repeat angiography 1 week later showed a stable C5 aneurysm and demonstrated two tandem anterior spinal artery aneurysms. Concurrent selective superior mesenteric artery angiography showed multifocal stenoses and fusiform branch aneurysms with main-trunk corrugation. The angiographic pattern favored a working diagnosis of SAM, although fibromuscular dysplasia and treatment-associated vasculitis remained considerations. No definite culprit spinal aneurysm was identified. Because intervention involved critical spinal arterial supply, the lesions were managed conservatively. Follow-up imaging over 11 months showed spinal hemorrhage resorption and near-resolution of the mesenteric aneurysms, with only a residual submillimeter anterior spinal artery aneurysm.