Failure to treat obstructive hydrocephalus with endoscopic third ventriculostomy in a patient with neurodegenerative Langerhans cell histiocytosis.

The second most frequent central nervous system involvement pattern in Langerhans cell histiocytosis (LCH) is a rare condition documented in a number of reports called "neurodegenerative LCH" (ND-LCH). Magnetic resonance images confirming the presence of the disease usually demonstrate striking symmetric bilateral hyperintensities predominantly in the cerebellum, basal ganglia, pons, and/or cerebral white matter. The authors here describe for the first time in the literature a patient with ND-LCH and concomitant hydrocephalus initially treated using endoscopic third ventriculostomy (ETV). This 9-year-old boy, who had undergone chemotherapy for skin and lung LCH without central nervous system involvement at the age of 10 months, presented with acute ataxia, headaches, and paraparesis and a 1-year history of gradually increasing clumsiness. Magnetic resonance images showed obstructive hydrocephalus at the level of the aqueduct of Sylvius and signs of ND-LCH. After registering high intracranial pressure (ICP) spikes with an intraparenchymal pressure monitor, an ETV was performed. A second ETV was required months later because of ostomy occlusion, and finally a ventriculoperitoneal shunt was placed because of ostomy reocclusion. Endoscopic third ventriculostomy was initially considered the treatment of choice to divert cerebrospinal fluid without leaving a ventriculoperitoneal shunt and to obtain biopsy specimens from the periinfundibular recess area. The third ventriculostomy occluded twice, and an endoscopic aqueduct fenestration was unsuccessful. The authors hypothesized that an inflammatory process related to late ND disease was responsible for the occlusions. Biopsy specimens from the infundibular recess and fornix column did not show histopathogical abnormalities. Increased ICP symptoms resolved with cerebrospinal fluid diversion. This case is the first instance of ND-LCH with hydrocephalus reported in the literature to date. Shunt placement rather than ETV seems to be the favorable choice in relieving elevated ICP.