Cladribine for the Management of Erdheim-Chester Disease in Adults

Erdheim-Chester Disease (ECD) is a rare, non-Langerhans cell histiocytosis characterized by foamy infiltrates of soft tissue and bone, with a histopathology that reveals CD68+, CD1a-, and S100histiocytes densely infiltrating organ systems such as bone, large vessels, heart, and lungs, and other tissues to name a few. Few chemotherapeutic options exist in the second line, of which one is cladribine. Cladribine (2-chlorodeoxyadenosine) is an anti-metabolite that predominantly affects blood cells by mimicking adenosine nucleosides, inhibiting adenosine deaminase, and thus disrupts the ability of the cell to repair DNA. Here we report three patients with varying sites of disease who achieved a response following treatment with cladribine. Although the efficacy of cladribine has been demonstrated in patients with ECD who primarily exhibited neurological symptoms, we present three patients in whom significant responses were achieved in disease distributed in long bones, pericardium, and retroperitoneum.