Dorsal dermal sinus with intramedullary abscess formation.

Dorsal dermal sinus, a congenital abnormality associated with spinal dysraphism, can serve as a path for spread of infection inside the spinal thecal sac with its sequelae. Intramedullary abscess formation is an uncommon complication and only about 20 cases have been reported in the English literature. We report MR appearances of three new cases.