Abstract 12746: A Case of Biopsy-Proven Erdheim-Chester Disease Manifesting With Pan-Aortitis, Coronary Artery Encasement, a Large Pericardial Effusion, Orbital Pseudotumors, and a Right Heart Mass

Abstract

A 72 year-old woman with a distant history of a cryptogenic right middle cerebral artery stroke presented with three days of fatigue, confusion, and recrudescence of old stroke symptoms. . Head and neck imaging demonstrated a small subarachnoid hemorrhage, orbital pseudotumors, cerebellar lesions, and circumferential thickening of the aortic arch and great vessels. Additional imaging of the chest, abdomen, pelvis, and legs revealed a large pericardial effusion, pan-aortitis, and sclerotic intramedullary lesions in both femurs. An electrocardiogram showed sinus rhythm, RBBB, and low voltage. Pulsus paradoxus was 10 mmHg. Laboratory analysis was notable for elevated serum inflammatory markers. Echocardiogram showed brief right ventricular diastolic inversion and a right atrioventricular groove mass. Diagnostic and therapeutic pericardiocentesis yielded 350cc of serosanguinous fluid, and evaluation for rheumatologic, infectious, and neoplastic etiologies was unremarkable. Cardiac magnetic resonance imaging (MRI) confirmed the presence of a right atrioventricular groove pseudotumor with avid late gadolinium enhancement and non-obstructive fibrotic encasement of the right and left anterior descending coronary arteries. The combination of pan-aortitis, orbital pseudotumors, pericardial effusion, coronary encasement, and right heart pseudotumor raised suspicion for Erdheim-Chester disease. Femoral bone biopsy revealed infiltration by CD68 (+), CD1a (-) histiocytes, confirming this diagnosis. Genetic testing identified a mutation in the gene for B-type RAF Kinase (BRAF) protein. Treatment with vemurafenib, a BRAF inhibitor, was initiated, and the patient’s disease has not progressed in the eighteen months since starting this treatment. Erdheim-Chester disease is a rare systemic illness caused by proliferation of non-Langerhans cell histiocytes. Cardiovascular manifestations—such as those seen in this case—complicate a majority of cases, and are the predominant cause of death. At least 50% of cases have mutations in the BRAF gene. While Erdheim-Chester disease has no known cure, vemurafenib represents a promising new therapy for BRAF mutation (+) cases.