Congenital interdural arachnoid cyst of the tentorium cerebelli.

Abstract

Intracranial interdural cyst is a rare lesion. The exact pathophysiology of these cysts remains unknown. We report an infant with interdural cyst of the tentorium cerebelli. Although the cyst mimicked an arachnoid cyst on pre- and postnatal magnetic resonance images, lateral suboccipital craniotomy revealed the cyst within the tentorium. Fenestration on the infratentorial side was performed with successful results. Histologically, the inner surface of the cyst was lined with arachnoid cells. We report detailed neuroradiological, intraoperative, and histological findings, and discuss the pathophysiology of the cyst in this case.