Erdheim-Chester disease (ECD) is a rare, multiorgan, non-Langerhans cell histiocytosis of uncertain origin, characterized by systemic xanthogranulomatous infiltration from CD68+CD1a- histiocytes. Skeletal involvement is present in up to 96% of cases with bilateral osteosclerosis of meta-diaphysis of long bones. Furthermore, in more than 50% of cases there is 1 extraskeletal manifestation. In this case report, we describe an interesting case of ECD with an extensive pan-cardiac and vascular involvement, in addition to skeletal, retro-orbital, and retroperitoneum one.A 44-year-old woman with a long history of exophthalmos referred to our hospital for elective surgical orbital decompression. At preoperative examinations a large pericardial effusion was discovered. Echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI) described an inhomogeneous mass involving pericardium and the right heart, abdominal aorta and its main branches and the retroperitoneum, suggestive for a systemic inflammatory disorder. Histological examination on a biopsy sample confirmed the diagnosis of ECD. Radiology showed the pathognomonic long-bone involvement. Surgical orbital decompression was performed and medical therapy with interferon-α (INF-α) was started.Among extraskeletal manifestations of ECD, cardiovascular involvement is often asymptomatic and thus under-diagnosed but linked to poor prognosis. This is why clinician should always look for it when a new case of ECD is diagnosed.