Abstract
Two cases of an epithelium-lined cyst of the quadrigeminal cistern are reported. Case 1, a 16-year-old girl, was admitted because of rapidly progressive visual disturbance. Neurological examination showed papilledema, abducens palsy, Parinaud's sign, hearing impairment, truncal ataxia, and incoordination. She was also slightly dull in response. Case 2, a 12-year-old girl, had experienced occasional headache and nausea for 3 months before admission. Neurological examination revealed early papilledema and cerebellar incoordination of the right side. In both cases, computed tomography scans revealed a large low density area in the quadrigeminal cistern and dilation of the third and lateral ventricles. The cyst wall was partially resected and a cyst-subarachnoid shunt was established in both cases with an additional ventriculo-peritoneal shunt in Case 1. Light microscopic examination of the cyst wall disclosed a layer of columnar or cuboidal epithelial cells and thin collagenous connective tissue. Electron microscopic study showed that the epithelial cells were mostly composed of non-ciliated cells, with a few ciliated cells. Basement membrane and junctional complexes were seen, but secretory granules were not found.
Literature on epithelium-lined cysts of the quadrigeminal cistern was reviewed and the histogenesis of the cyst was discussed. Although the origin of epithelium-lined cysts is still controversial, histological findings in the present cases indicate that the cysts originated from the primitive neuroepithelium, because of the resemblance to the choroid plexus.
