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

BACKGROUND: 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. CASE DESCRIPTION: 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. CONCLUSIONS: 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.