Enlarging Ventriculus Terminalis in a Patient With Polyarteritis Nodosa.

Ventriculus terminalis (VT) is a cystic embryological remnant within the conus medullaris that normally regresses after birth. In rare cases, it may persist into adulthood and give rise to neurologic symptoms. The pathogenesis remains unclear but is thought to be related to failed embryonic regression with other proposed possible etiologies including vascular disturbances. We present an intriguing case of a slow-growing VT in a woman with progressive neurologic symptoms who experiences symptomatic relief following thoracic laminectomy and fenestration. Our case is the first to present a unique association with polyarteritis nodosa and only the third to report a case of documented enlargement of the VT over time successfully treated with surgical fenestration.