SHM Converge Scientific Abstract ePoster Gallery-Diagnostic and Therapeutic Challenges of Multisystem Erdheim-Chester Disease in a Braf-Wild-Type, Map2k Mutant Patient

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This case describes a 79-year-old man with Erdheim-Chester disease (ECD), a rare multisystem histiocytic disorder caused by infiltration of foamy histiocytes in bones and organs. His illness began with a suprapubic mass, but early biopsies were nondiagnostic. Over time, he developed painful orbital inflammation with proptosis and vision loss, diffuse bone pain, weakness, weight loss, and evidence of involvement of the heart, pericardium, pituitary region, dura, and bone marrow.<br /><br />Multiple diagnostic procedures were initially unrevealing, including a tibial biopsy and lymph node biopsies. However, imaging strongly suggested a widespread infiltrative process: bone scan, PET/CT, cardiac MRI, and brain/orbit MRI showed multifocal skeletal and soft tissue disease. Bone marrow biopsy was highly suspicious for a histiocytic neoplasm, and BRAF V600E testing was negative, supporting a diagnosis of BRAF-wild-type ECD. The case highlights the importance of bone marrow evaluation and molecular testing when peripheral biopsies fail.<br /><br />Treatment was complex and required coordination across specialties. He initially improved on binimetinib, a MEK inhibitor targeting the MAPK pathway, but therapy was stopped because of a significant decline in left ventricular ejection fraction. He was then switched to cobimetinib, which improved orbital and systemic symptoms, and his cardiac function partially recovered with close monitoring. Additional symptom-directed therapies included palliative radiation for bone pain, anakinra, pegylated interferon, nutritional support, and management of endocrine and cardiovascular complications.<br /><br />The main lessons are that ECD often presents nonspecifically, diagnosis is frequently delayed, and early molecular testing is essential to guide therapy. MEK inhibitors can be effective, but cardiac toxicity requires careful surveillance. Multidisciplinary care is critical to improve outcomes in advanced multisystem disease.

Asset Subtitle

Linh N. Vo

Meta Tag

Author List Ahmadreza Ghasemiesfe, Lee D. Lam, Linh N. Vo, Shotaro Naganawa

Category Clinical Vignettes

Concept Erdheim-Chester Disease

Concept MAPK Pathway

Concept MAP2K Mutation

Concept MEK Inhibitor

Concept Cardiac Monitoring

Distinguished Non-Finalist

Presenter Organization University of California, Davis School of Medicine

Presenting Author Linh N. Vo

Track Adult

Keywords

Erdheim-Chester disease

histiocytic disorder

BRAF wild-type

MEK inhibitor

binimetinib

cobimetinib

cardiac toxicity

orbital inflammation

bone marrow biopsy

multisystem disease

Erdheim-Chester Disease

MAPK Pathway

MAP2K Mutation

MEK Inhibitor

Cardiac Monitoring