Increased size of a gas-filled intradural cyst causing acute foot drop: a case report.

We describe the case of a 76-year-old man presenting with a gas-filled intradural cyst that increased in size over a 10-month period and caused acute bilateral foot drop. The gas-filled intradural cyst was resected from the adherent cauda equina, and histopathological examination identified cystic tissue with degenerated fibrocartilage. Leg pain disappeared immediately following surgery, and the bilateral foot drop resolved within 8 months.