Childhood-onset Erdheim-Chester disease in the molecular era: clinical phenotypes and long-term outcomes of 21 patients.

Erdheim-Chester disease (ECD) is a rare histiocytic disorder that can present as a localized infiltration of foamy histiocytes or a multisystem disease that may be life-threatening. It is extremely rare in children. Pegoraro and colleagues present the clinical and molecular features of 21 patients with pediatric ECD through a large international collaboration, documenting that it resembles its adult counterpart, with similar molecular features and responses to agents targeting BRAF and MEK.