Arachnoid cyst

Spinal cysts responsible for compressive syndromes of the medulla or cauda equina may be classified on a pathogenetic basis: congenital (due to persistence of the neuro-enteric canal); acquired (pseudocyst of the cerebrospinal fluid); due to altered development, on a congenital or degenerative basis (arachnoid cyst, meningeal diverticula, perineural cyst). Arachnoid cyst, a rare condition of which less than a hundred cases have been reported, gives rise to a compressive syndrome which runs a very slow course. Similar clinical characteristics have recently brought about a certain terminological confusion, especially with regard to the neuro-enteric cysts. The writers illustrate the clinical, radiographic and anatomo-pathological features of a case observed personally by them. They emphasize the similarities and differences as compared to kindred morbid processes.