[Cerebellar syndrome, exophthalmos and secondary hypogonadism in Erdheim-Chester disease].

We present a 50-year-old patient with a slowly progressive cerebellar syndrome, left-sided exophthalmos, secondary hypogonadism, and multiple pleomorphous skin alterations. The diagnosis of Erdheim-Chester disease was established by the radiological detection of a left-sided retrobulbar space-occupying mass, a hypophysial stalk lesion, alterations in both cerebellar hemispheres, retroperitoneal imbibition, osteolytic/osteosclerotic changes in the metaphysis and diaphysis of the long bones, and a skin biopsy with histological detection of a non-Langerhans-cell histiocytosis. The etiology of the Erdheim-Chester disease is unknown. Cerebral manifestations of this rare disease have been documented in only a very few cases. Whereas the extracranial alterations are due to pathologic histiocyte proliferation, cerebellar changes are considered to be the result of demyelinisation or infiltration of xanthogranulomas.