LAUSR

BACKGROUND Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis that typically occurs in middle-aged patients. It is usually characterized by multifocal osteosclerotic lesions of the long-bones, however many cases have extraskeletal involvement. Central nervous system (CNS) involvement is common, but isolated CNS involvement at presentation has rarely been reported. CASE DESCRIPTION Here we report two cases of dural-based ECD mimicking meningioma on imaging with no other identified sites of disease. CONCLUSION ECD is a rare disease, with isolated CNS involvement reported only a few times in the literature. The significance of this presentation requires additional study and long-term follow up.