RT Journal Article SR Electronic T1 An unusual case of interstitial lung disease in a patient with cardiopulmonary syndrome as the initial presentation of Erdheim-Chester disease JF BMJ Case Reports FD BMJ Publishing Group Ltd SP bcr-2017-220659 DO 10.1136/bcr-2017-220659 VO 2017 A1 Domingo Franco-Palacios A1 April McDonald A1 R Neal Aguillard A1 Allen Berry YR 2017 UL http://casereports.bmj.com/content/2017/bcr-2017-220659.abstract AB Erdheim-Chester disease (ECD) is a very rare disorder with only approximately 600 cases reported in the literature. ECD has been recently reclassified as a histiocytic dendritic cell neoplasm. The clinical spectrum ranges from asymptomatic tissue accumulation of histiocytes to invasive tissue infiltration, which can cause fulminant multisystem failure. It typically presents with bone pain and constitutional symptoms. Extraosseous manifestations are not uncommon. ECD-associated interstitial lung disease has been described in 20%-35% of patients. Diagnosis is primarily by tissue biopsy and immunohistochemistry showing xanthogranulomas composed of foamy histiocytes that stain positive for CD68, CD14 and CD163 and negative for CD1รก and langerin. We report a case of ECD in a young man with cardiopulmonary involvement who presented with haemoptysis and dyspnoea.