Erdheim-Chester Disease: Case Report with Aggressive Multisystem Manifestations and Review of the Literature.

Erdheim-Chester disease (ECD) is an extremely rare and aggressive form of non-Langerhans cell histiocytosis. ECD usually presents with bone pain in adults aged 40-60. Its etiology is unknown but it is thought to be either a reactive or neoplastic disorder. Recently, mutation of the proto-oncogene BRAF (BRAFV600E) has been found in more than 50% of cases. The multisystemic form of ECD is associated with significant morbidity, which may arise due to histiocytic infiltration of critical organ systems. The common sites of involvement are the skeleton, central nervous system, cardiovascular system, lungs, retroperitoneum, and skin. Current available treatment is interferon alpha as the first line of treatment. Treatment with other agents is based on anecdotal case reports. Cladribine, anakinra, and vemurafenib (BRAF inhibitor) are currently advocated as promising second-line treatments for patients whose response to interferon alpha is unsatisfactory. Herein, we are reporting a middle-aged Saudi male patient with an aggressive type of ECD and highlighting the clinical, radiological, and pathological manifestations associated with ECD and the various treatment options and patient follow-up.