OBJECTIVE AND IMPORTANCE: 

Perineurioma, a rare benign nerve sheath neoplasm occurring in either an intraneural or soft tissue form, has never been reported to arise in the central nervous system.

CLINICAL PRESENTATION: 

We describe the clinical, radiological, and pathological features of a perineurioma arising in the choroid plexus of the third ventricle in a 65-year-old woman and causing obstructive hydrocephalus.

INTERVENTION: 

The lesion, apparently unassociated with a nerve, was gross totally resected by frontal craniotomy using a left-sided transcallosal approach. Short-term follow-up showed no evidence of recurrence.

CONCLUSION: 

Perineurioma of the variety found in soft tissue may occur in the central nervous system, wherein it shows the typical light microscopic, immunohistochemical (epithelial membrane antigen- and Collagen IV-positive, S-100 protein-negative), and ultrastructural (pinocytotic vesicles, discontinuous basement membrane) features.