Iatrogenic intraspinal epidermoid tumor: myelo-CT and MRI diagnosis.

An 11-year-old boy, treated for acute lymphatic leukemia at the age of 2 with intrathecal injections of Methotrexate, presented with a two year history of pain and signs of lumbo-sacral lesion. MRI, myelography and myelo-CT demonstrated an intradural L4-L5 epidermoid tumor which was removed. Iatrogenic implantation of epithelial cells at the age of two with lumbar punctures is most likely. Decline in incidence of lumbar iatrogenic epidermoid cysts, now an exceedingly rare event, is probably related to improved needles for lumbar punctures.