Neurologic Manifestations of Erdheim-Chester Disease (P3.273)

OBJECTIVE:To characterize the neurologic features of Erdheim-Chester Disease (ECD).BACKGROUND:ECD is a non-langerhans histiocytosis characterized by macrophage accumulation in bone, kidneys, retroperitoneum, orbits, pituitary stalk, and the nervous system. It is distinguished from Rosai-Dorfman and Juvenile Xanthogranuloma by the presence of CD68+, CD163+, CD1a-, CD207-, S100+/-, and anti-factor XIIIa+ foamy macrophages on biopsy. Treatments include immunomodulators and BRAF/MAP kinase inhibitors. A retrospective study suggests that half the patients have neurologic involvement, but the presentation remains incompletely described beyond case reports and small series.DESIGN / METHODS:Prospective, observational study of 57 patients with biopsy-confirmed ECD. Evaluation included neurologic assessment, 3T MRI (brain, orbit, pituitary) and neurophysiologic testing.RESULTS:96[percnt] of the patients had clinical or radiographic pathology above the neck. 86[percnt] of the patients exhibited clinical neurologic deficits, and 52[percnt] had CNS pathology on MRI. Clinical presentation includes cranial neuropathies and brainstem involvement (56[percnt]), cognitive decline (44[percnt]), ataxia (40[percnt]), neuropathy (54[percnt]), vision impairment (25[percnt]) and seizures (9[percnt]). CNS radiologic abnormalities included T2/FLAIR lesions (69[percnt]), generalized atrophy (27[percnt]), and empty sella syndrome (6[percnt]). Enhancement was observed in brain parenchyma (17[percnt]), meninges (6[percnt]) and optic nerve (2[percnt]). CNS lesions were ill-defined, variably enhancing (60[percnt] of lesions), minimally displacing, and unaccompanied by edema. Infiltrates were observed in the pituitary, scalp, orbits and extra-ocular musculature (contributing to proptosis and gaze palsies) as well as peripheral or optic nerves. Nerve conduction testing revealed small fiber polyneuropathy (20[percnt]), mononeuropathy (31[percnt]) or polyradiculopathy (3[percnt]). 1 patient had comorbid ocular myasthenia gravis.CONCLUSIONS:Neurologic dysfunction is a common cause of morbidity and increased mortality in ECD, occurs at multiple levels of the neuraxis, and mimics various neurologic disorders including glioma, lymphoma, or multiple sclerosis. Imaging alone grossly underestimates the extent of neurologic involvement. This study highlights the importance of thorough neurologic evaluation in histiocytosis patients. Disclosure: Dr. Boyd has nothing to disclose. Dr. Dave has nothing to disclose. Dr. O9Brien has nothing to disclose. Dr. Gahl has nothing to disclose. Dr. Estrada-Veras has nothing to disclose.