Immunopathological Analysis of Erdheim-Chester Disease with Massive Ascites

We treated a 77-year-old woman with pleural and pericardial effusion and ascites. Initially, collagen vascular disease was suspected due to the presence of anti-centromere antibodies and suspected complication of pulmonary arterial hypertension. However, soft-tissue abnormalities surrounding the bilateral kidneys detected on computed tomography (CT) and symmetrical lesions of the long bones detected on bone scintigraphy made us consider a diagnosis of Erdheim-Chester disease (ECD), which is a rare form of histiocytosis. We immunochemically analyzed the cells derived from the ascites in detail and confirmed the diagnosis. Immunocytochemical analyses may therefore help to achieve a better understanding of the pathogenesis of this rare disease.