Arachnoid cyst of the cavum velum interpositum associated with cavum septum pellucidum and cavum vergae

Abstract

A cavum velum interpositum is a normal variaton which is often detected incidentally in asymptomaticindividuals. However, arachnoid cyst of the cavum velum interpositum is extremely rare and may causesymptoms similar to those of a third ventricular mass. On imaging, the main differentials of this cyst are; cysticdilatation of the cavum velum interpositum, cavum vergae cyst, arachnoid cyst of the quadrigeminal cistern,and epidermoid cyst. We present a case of an arachnoid cyst of the cavum velum interpositum coincidentallyassociated with the cavum septum pellusidum and cavum vergae. The cavum velum interpositum is a rarelocation for the arachnoid cysts. Accurate diagnosis of the arachnoid cysts of the cavum velum interpositum isimportant as they cause serious symptoms which can be reversed by surgical treatment.