Pathogenesis and diagnostic pitfalls of ventricular diverticula: case report and review of the literature.

Objective and Importance: Ventricular diverticula are local herniations of the ventricular system occurring in association with severe, long-standing hydrocephalus. Variability in the extent and location of these ventricular pouches may produce misleading radiological conformations and raise diagnostic challenges. In this report, we discuss the pathogenesis and differential diagnosis of ventricular diverticula on the basis of a case illustration.
Clinical Presentation: We report the case of a 38-year-old woman presenting with hydrocephalus secondary to an obstructive lesion of the third ventricle. A large, dilated structure compressing the brainstem was present in the posterior fossa.
Intervention: The posterior fossa lesion was identified as an atrial diverticulum by injection of contrast medium into the right lateral ventricle, which led to immediate enhancement of the infratentorial cavity. Ventricular drainage and removal of the third ventricular lesion, a colloid cyst, allowed progressive collapse of the diverticulum and symptom resolution.
Conclusion: This report discusses the pathogenesis of ventricular diverticula and demonstrates that ventriculography can be used to differentiate atrial diverticula from other posterior fossa lesions when time-consuming multiplanar magnetic resonance imaging cannot be afforded on an emergency basis.