Intracranial Neurenteric Cyst with an Enhanced Mural Nodule and Melanin Pigmentation: Radiologic-Pathologic Correlation.

Abstract

An intracranial neurenteric cyst (NC) is a rare congenital benign lesion that usually has a well-demarcated cystic appearance without contrast enhancement on magnetic resonance imaging (MRI). In particular, an intracranial NC with an enhanced mural nodule is extremely rare. A 20-year-old man presented with left-sided hearing disturbance and headache. On MRI, a cystic mass was seen in the prepontine cistern that significantly compressed the brainstem. The lesion was hyperintense on T1-weighted images, and contained a solid component that appeared with marked hypointensity on T2*-weighted images and slight enhancement. The cystic wall was removed via a left transcondylar fossa approach. Histopathologic findings showed an NC with a solid component and melanin pigmentation. The solid component showed xanthogranulomatous changes, with evidence of an old hemorrhage, and was strongly adherent to the brainstem. We present this rare case and emphasize that an NC should be considered in the differential diagnosis of intracranial cystic lesions with an enhanced mural nodule.