Transthyretin-related Familial Amyloidosis: A Cause of Leptomeningeal Enhancement, Superficial Siderosis, and Engorged Intradural Spinal Veins

We report a case of transthyretin-related amyloidosis in a patient who presented with intracranial and spinal leptomeningeal enhancement, pial siderosis, and engorged intradural spinal veins. In isolation, differential considerations of these 3 findings are broad. Although leptomeningeal enhancement and pial siderosis have been reported in this condition, this is the first time engorged pial vessels have been described in the MR imaging literature. The combination of all 3 finding may be specific for the diagnosis of leptomeningeal transthyretin‐related familial amyloidosis.