ERDHEIM-CHESTER-DISEASE WITH EXTENSIVE INTRAAXIAL BRAIN-STEM LESIONS PRESENTING AS A PROGRESSIVE CEREBELLAR SYNDROME

We report a rare case of Erdheim-Chester disease (ECD) presenting as a progressive cerebellar syndrome and diabetes insipidus. On magnetic r esonance imaging, a 7-mm extraaxial, enhancing mass was seen envelopin g the right vertebral artery and was confirmed at autopsy to represent an adventitial xanthoma with lipid-laden, foamy histiocytes. The cere bellar syndrome most likely resulted from extensive histiocytic infilt ration of the pons, particularly the basis pontis and middle cerebella r peduncles.