Neuroradiology

Lumbar puncture, sequelae, in epidermoid cyst

When lumbar punctures were performed with nonstylet needles or with ill-fitting trochars, there was a significant risk that epidermal elements might be carried into the subarachnoid space from the needle track. These implants grow slowly, resulting in an extramedullary intradural mass that adheres to the nerve roots and pia-arachnoid. They were a late complication of lumbar puncture occurring between 1 and more than 20 years from the puncture (see epidermoid tumour).

Symptoms include progressive radicular and back pain, gait abnormalities and sphincter disturbances. MR shows an intradural mass, usually lobulated, with a CSF-like signal. See intradural extramedullary tumour.

GS