Erdheim-Chester disease progression from miliary pulmonary nodules to large tumours

Erdheim-Chester disease (ECD), a rare form of non-Langerhans cell histiocytosis, affects long bones, the retroperitoneal region, and the central nervous, cardiovascular, and pulmonary systems. Most patients with ECD show interlobular septal thickening, centrilobular micronodules, and ground glass opacities on chest computed tomography (CT). We encountered a 66-year-old man with ECD who presented at first visit with randomly distributed multiple pulmonary nodules and who then developed large tumour shadows, observed on chest CT. To our knowledge, this random distribution pattern of multiple pulmonary nodules has not previously been reported.