Large Parenchymal Perianeurysmal Cyst: A Case Report

Parenchymal perianeurysmal cysts are rare. We report a case of 50-year-old woman who presented with persistent headaches and episodes of vomiting for the last 2 months. Magnetic resonance imaging of the brain showed a well-defined solitary cystic lesion with a mural nodule measuring 5.4 × 5.2 × 4.6 cm in the right basifrontal region. The mural nodule was cortically based. It was hypointense on T2-weighted fluid-attenuated inversion recovery and showed intense contrast enhancement with few nonenhancing areas—no evidence of diffusion restriction. The cyst wall was nonenhancing, and magnetic resonance angiogram was unremarkable. Differential diagnoses included intra-axial gliomas such as ganglioglioma and pleomorphic xanthoastrocytoma. Right pterional craniotomy and a transcortical approach were made. Subtotal excision of cyst and clipping of right middle cerebral artery bifurcation thrombosed aneurysm were done. After 6 months of follow-up, patient is stable without any deficits. A parenchymal perianeurysmal cyst is a rare entity; it is crucial to be considered a differential diagnosis in any cystic lesion with the mural nodule.