Erdheim-Chester Disease with a Posterior Fossa Tumour Mimicking Neurosarcoidosis: a Case Report

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis described in 1930 by Jakob Erdheim and William Chester; it presents as a multisystemic entity that forms xanthogranulomas, foamy histiocytes surrounded by fibrotic tissue. Lesions are commonly located in long bones, central nervous system (CNS), cardiovascular system, lungs, kidneys, and skin. The CNS is involved in approximately 50% of cases and can compromise both extra- or intra-axial structures and therefore can mimic schwannomas or meningiomas, among other mass lesions [7, 4]. Clinical presentation will differ from patient to patient; thus, diagnosis depends greatly on imaging, immunohistochemistry, and genetic findings within the pathology analysis [8]. The pathogenesis of this disease remains unknown. It is most commonly found in the middle-aged male population [1, 2]. Here, we present a case of a middle-aged woman with an extra-axial lesion that was initially considered to be neurosarcoidosis proving the diagnostic challenge this entity implies.