[Dermoid cyst of the conus medullaris revealed by chronic urinary retention. Contribution of imaging].

We report a case of congenital dermoid cyst of the conus medullaris without associated dysraphic lesion treated surgically. An 18-year-old man had a one-year history of bladder sphincter disorders and more recent acute renal failure with urinary tract infection. The diagnosis of intramedullary tumor was provided by myelo CT and MRI confirmed by histology. At 10-month follow-up, the postoperative course was good.