Study Objective:  This research study is a Phase II clinical trial studying a chemotherapy drug Lenalidomide as a possible treatment for one of three histiocyte disorders: Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), or histiocytic sarcoma (HS).

Sponsor:  Dana-Farber Cancer Institute

Trial Contact Information:  Eric Jacobsen, MD, 617-632-6633, [email protected]

Requested Patient Involvement: Patients diagnosed with ECD 18 years and older.

ClinicalTrials.gov Identifier: NCT02523040