Neurological manifestations and neuroradiological presentation of Erdheim-Chester disease: report of 6 cases and systematic review of the literature.

Erdheim-Chester disease (ECD) is a rare, non-Langerhans form of histiocytosis of unknown etiology that affects multiple organs. We report 6 cases of ECD with neurological involvement and neuroradiological abnormalities on brain MRI. A literature review revealed 60 other cases of ECD with neurological involvement. We therefore analyzed 66 ECD patients with neurological involvement. Cerebellar and pyramidal syndromes were the most frequent clinical manifestations (41% and 45% of cases), but seizures, headaches, neuropsychiatric or cognitive troubles, sensory disturbances, cranial nerve paralysis or asymptomatic lesions were also reported. Neurological manifestations were always associated with other organ involvement, especially of bones (at least 86%) and diabetes insipidus (47%). Neurological involvement was responsible for severe functional handicaps in almost all patients and was responsible for the death of 6 of the 66 patients (9%). Neuroradiological findings could be separated into three patterns: the infiltrative pattern (44%), with widespread lesions, nodules or intracerebral masses, the meningeal pattern (37%), with either thickening of the dura mater or meningioma-like tumors, and the composite pattern (19%), with both infiltrative and meningeal lesions.