A 28-year-old lady presented with headache and vomiting since 11/2 years. She complained of difficulty in gripping objects with left upper limb, gait unsteadiness with tendency to sway to the left side, dysarthria and nasal regurgitation on swallowing fluids. On examination, bilateral gaze evoked downbeat nystagmus was present. Gag reflex was sluggish bilaterally but uvula was central. There was drooping of right shoulder and weakness of right sternocleidomastoid. Left cerebellar signs were present with ataxic gait. Bulk and tone of muscles was normal.\nCT [] showed a hyperdense extraxial lesion in left side posterior fossa, compressing brainstem and distorting the 4th ventricle with obstructive hydrocephalus. On MRI [], it appeared iso- to mildly hypointense on T2 weighted images and hyperintense on T1 weighted images without suppression of signal on fat saturated images. The lesion measured 5.4 × 4.2 × 5.34 cms. There was no obvious enhancement on administration of contrast. There was no restriction diffusion. On the anterior aspect of the lesion, just to the left of midline, there was a T1- and T2 hypointense focus that corresponded with slightly increased density on plain CT and showed blooming on SWI (likely calcification). The lesion showed facilitated diffusion. MRS showed a large NAA like peak at 2.02 ppm.\nShe underwent midline suboccipital craniectomy and near total excision of the lesion. Histopathology showed a cyst wall composed of pseudostratified ciliated columnar epithelium (black arrow) with extensive areas of squamous metaplasia suggestive of neuroenteric cyst.
A 7 month old girl presented with complaints of poor feeding, excessive crying and downgaze preference since 1 month. MRI [] showed a CSF-intensity cystic lesion of 7 × 5.7 × 5.8 cm size in left side of posterior fossa compressing the brainstem and cerebellar hemisphere to right with obstructive hydrocephalus and periventricular hyperintensities. The child underwent midline suboccipital craniotomy and decompression of cyst. On histopathology, the cyst wall was lined by pseudostratified ciliated cuboidal to flattened epithelium (black arrow) with a subepithelium composed of fibrocollagenous tissue with dilated vascular channels. On microscopic examination, the findings were suggestive of a neuroepithelial cyst, but based on the immunohistochemical properties, a final diagnosis of neuroenteric cyst was made.