Giant cyst of the septum pellucidum: case report.

Symptomatic cysts of the septum pellucidum are rare. Up to 1969, 17 published cases were considered to be symptomatic. In the case report here, a 9-week-old girl was hospitalized because of disproportionate progressive enlargement of the head, lumbar myelomeningocele, and a history of generalized seizures. A giant septum pellucidum cyst was demonstrated on Conray ventriculography and later on computerized tomography (CT) scanning. Aqueductal stenosis was suspected. The cyst was excised at craniotomy. A ventriculoperitoneal shunt was required to treat the accompanying hydrocephalus.