Morphology and immunohistochemistry of a symptomatic septum pellucidum cavum Vergae cyst in man.

The cavum septi pellucidi (CSP) and cavum Vergae (CV) are persistent, primitive, or acquired, midline structures of adult human brain. It is customary to distinguish between the non-communicating and the communicating cava, depending on whether the cavum communicates with the cerebral ventricular system or not. Only a few cases of symptomatic non-communicating cava, called septum pellucidum and cavum Vergae cysts, have been described in the literature. In this study, the authors describe the morphological, histological and histo-immunological characteristics of an additional case of septum pellucidum-cavum Vergae cyst in a forty-year-old man who died the day following a ventriculo-peritoneal shunt. We have found a communication between the CSP and the leptomeningeal space of the anterior interhemispheric fissure, in the absence of subarachnoid haemorrhage. The authors discuss the origin of the intracystic fluid and the classification of the CSP.