Arachnoid Cyst of the Velum Interpositum: Coincidence with Multiple Cranial Neuropathies

Abstract

Arachnoid cyst of the velum interpositum is unusual and causes symptoms similar to those seen with a third ventricular mass. This report describes a case in which the arachnoid cyst occupied the cistern of the velum interpositum and was coincident with multiple cranial neuropathies. The patient was treated by endoscopic fenestration of the cyst. The surgery resulted in decreased in the size of the cyst but aggravation of cranial neuropathies. The patient underwent methylprednisolone pulse therapy and intravenous immunoglobulin administration under the impression of the multiple cranial neuropathies and recovered completely 3 months later. The authors conclude that combined neurological disease that needs medical treatment should be differentiated and priority of the treatment should be determined carefully if arachnoid cyst is associated with unrelated or ambiguous neurological symptoms and signs. Careful considerations of cause and effect may avoid an unnecessary surgical manipulation.