Disease Directory Erdheim-Chester Disease
Immune

Erdheim-Chester Disease

Also known as: ECD, non-Langerhans cell histiocytosis, xanthogranulomatous histiocytosis

Prevalence

Approximately 1,500-2,000 cases reported worldwide

Onset

Middle to older adulthood; median age at diagnosis ~55 years

Type

Histiocytic neoplasm / inflammatory myeloid neoplasm

Gene

BRAF V600E (majority)

About Erdheim-Chester Disease

Erdheim-Chester Disease is a rare clonal histiocytic neoplasm characterized by infiltration of foamy CD68+/CD1a- histiocytes into virtually any tissue, most characteristically causing bilateral symmetrical long bone osteosclerosis, periaortic and perirenal soft tissue infiltration (hairy kidney), and retroperitoneal fibrosis. Activating MAPK pathway mutations, most commonly BRAF V600E, are present in approximately 50-60% of cases, enabling targeted therapy with vemurafenib and other BRAF/MEK inhibitors. CNS and cardiovascular involvement, including pericardial disease and right atrial pseudotumor, are the leading causes of morbidity and mortality.

Common Clinical Features

Bilateral diaphyseal long bone pain and osteosclerosis on imaging Retroperitoneal fibrosis and perirenal infiltration (hairy kidney on CT) Diabetes insipidus from hypothalamic/pituitary stalk infiltration Xanthelasma and periorbital xanthomas Interstitial lung disease and pleural thickening Pericardial infiltration and right atrial pseudotumor CNS involvement (cerebellar ataxia, pyramidal signs)

Clinical Trial Eligibility Tips

What to know before applying to Erdheim-Chester Disease trials.

BRAF V600E status from tissue biopsy (CD68+/CD1a- histiocytes) is required before applying to BRAF inhibitor trials; if initial biopsy was not tested, reflex BRAF testing on archival tissue may be possible

MEK inhibitor trials (cobimetinib, trametinib) enroll BRAF wild-type and BRAF mutant patients; confirm full MAPK pathway mutation profile including MAP2K1, NRAS, KRAS before applying

Cardiac and CNS involvement staging with cardiac MRI and brain MRI with gadolinium is typically required at screening; compile current imaging within 3 months of application

Patient Resources

Patient Organization

Erdheim-Chester Disease Global Alliance

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Natural History Registry

ECD Global Alliance Registry

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Orphanet

European reference resource for rare diseases (ORPHA:35687)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting Erdheim-Chester Disease trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for Erdheim-Chester Disease. Updated daily.

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