[Primary cauda equina epidermoid cyst. A case report].

A primary epidermoid cyst of the cauda equina was diagnosed in an eleven-year-old boy. The patient had a previous two months history of lumbar pain with unilateral L 4 radicular pain. The diagnosis of an epidermoid cyst of the cauda equina, suspected by MRI, was confirmed by histology following surgery. Wide tumor resection, as complete as possible, was performed with minimum trauma. Presence of an epidermoid cyst in the filum terminale is a rare finding, few cases have been reported in the literature. However, surgical treatment and favorable post-operative course are similar to that observed in intraspinal localizations. MRI is helpful for the preoperative and differential diagnosis and for post-operative follow-up.