Glucosteroid treatment of keratin meningitis following removal of a fourth ventricle epidermoid tumour.

It was Cruveilhier in 1829 who gave the picturesque description of intracranial keratinous tumours, 'tumeurs perlees'. Bailey described the first successful removal of an intracranial pearly tumour in 1920. In the second case reported in that paper and in two subsequent cases reported by Bailey in 1924 in which only a subtotal removal of this lesion could be safely effected, the postoperative course was complicated by spiking fever and meningismus, but repeated cultures of the cerebrospinal fluid were negative. The aseptic or chemical aetiology of this meningitic syndrome following removal of these tumours has been amply documented. In all instances the common factor in the pathogenesis of the meningeal reaction has appeared to be the contamination of the subarachnoid space by tumour contents. Recently, a report was made of a case of keratin chemical meningitis following the removal of a posterior fossa dermoid. A simple test involving microscopic examination of the cerebrospinal fluid under polarized light afforded identification of the presence of birefringent keratin in the cerebrospinal fluid (Cantu, Moses, Kjellberg, and Connelly, 1966). This test also confirmed the presence of keratin in the lumbar cerebrospinal fluid in the following case, which is being reported to illustrate the striking therapeutic value of glucocorticoids in the treatment of aseptic chemical meningitis.