Fig 2.

Patient 2.

A, Sagittal T1-weighted image demonstrates an ovoid mass (arrows) in the midline anterior to the pontomedullary junction. The cyst is hyperintense to brain parenchyma and CSF (reproduced from Osborn AG, et al, Diagnostic Imaging: Brain, Amirsys/Elsevier, 2004).

B, Axial FLAIR scan in the same patient shows that the mass remains hyperintense and extends from the midline into the right lower cerebellopontine angle.

C, Representative histopathology of a NE cyst showing pseudostratified, ciliated, columnar epithelium, which is poor in mucin-producing cells.