Third ventricular diverticulum of the suprapineal recess can be a rare and confounding complication of chronic hydrocephalus: A case report with 2-year follow-up

Purpose: Chronic hydrocephalus is rarely seen in developed countries due to the widespread availability of CT scans for diagnosis and early treatment. In developing countries, it is more frequently encountered along with its rare complication of diverticulum formation. Methods: We report a case of a previously healthy 6 year old girl who presented with a 10 day history of headache, 3 day history of drowsiness and a single episode of generalized tonic clonic seizures. We review the literature on such cases and include imagining studies at follow up. Results: A CT scan done outside our hospital had been reported to be demonstrating a posterior fossa arachnoid cyst with resultant obstructive hydrocephalus. We first placed an external ventricular drain and performed an MRI of the brain to further characterize the lesion. It was again reported as an arachnoid cyst but on further scrutiny it was appreciated that it was in fact a third ventricular diverticulum of the suprapineal recess. She underwent ventriculoperitoneal shunt placement which led to resolution of the hydrocephalus as well as the diverticulum. Conclusion: These diverticulae develop secondary to ventricular rupture in the setting of chronic untreated hydrocephalus. This pathology was first described in 1940 and over the years its identification has decreased due to a much lower incidence of chronic untreated hydrocephalus.