Cerebral and pulmonary histiocytosis X. Neurologic manifestations disclosing a pseudotumoral formation on the floor of the 4th ventricle

: The authors report a case of histiocytosis X which presented with neurological manifestations in a 20 year old man: episodes of headache with vomiting, followed, three months later, by the development of paralysis of the right 6th and 7th cranial nerves associated with nystagmus. The CT scan revealed a tumour-like lesion on the floor of the IVth ventricle with a long axis of 18 mm. The chest x-ray revealed diffuse nodular opacities in the pleural and apical regions with features suggestive of histiocytosis X. The diagnosis was confirmed by surgical biopsy of the typical pulmonary nodules which were rich in histiocytes with X bodies on electron microscopy. The neurological signs disappeared after one month of treatment with Prednisone (1 mg/kg/day) and Vincaleukoblastine (10 mg/week). By the 3rd month, the pulmonary lesions were reduced and the intra-ventricular formation had regressed by 40%. In the authors' series of 29 cases of confirmed histiocytosis X in adults, the present case is the only one with a clinical neurological presentation, apart from 3 cases of diabetes insipidus. A review of the literature confirms the rarity of this type of presentation. The suggestion of the diagnosis by the chest x-ray appearance enabled a dangerous neuro-surgical operation to be avoided.