Obstructive Hydrocephalus and Chemical Meningitis Secondary to a Ruptured Spinal Epidermoid Cyst.

Epidermoid cysts of the spinal cord may rupture, resulting in keratin dissemination in the subarachnoid space, in the ventricles, and along the central canal of the spinal cord causing meningitis, myelopathic changes, or hydrocephalus.A 53-year-old woman with no past medical history presented with a 2-week history of headache located in the occipital region associated with neck pain. Brain magnetic resonance imaging demonstrated multiple fat droplets scattered throughout the subarachnoid and intraventricular spaces with significant edema of the right posterior temporoparietal lobes with trapping of the right temporal horn of the lateral ventricle and atrium. An intracranial lesion could not be observed in the study. The spinal region was suspected as the possible culprit, and spinal imaging showed a large cystic lesion at the level of the conus medullaris. The patient underwent neuronavigation endoscopic exploration of the right lateral ventricle with flushing of the keratin particles followed by a posterior lumbar decompression with resection of the epidermoid cyst. Pathology was consistent with an epidermoid cyst. Successful recovery with improvement in symptoms was quickly observed.When an epidermoid cyst is suspected but no intracranial lesion is found, the intraspinal area should be studied. Rupture of a spinal epidermoid cyst may cause meningitis and inflammation producing obstructive hydrocephalus. We present this rare entity and describe the diagnostic and surgical techniques used.