Erdheim-Chester disease (ECD) characterized by proliferation of foamy histiocytes and their infiltration into various tissues and organs, typically the long bones of the lower extremities, is a rare disease of the non-Langerhans cell histiocytosis group. In the patients with ECD during examinations by imaging methods various pathologic changes are described, including osteosclerosis, infiltration of the hypophysis, periaortic fibrosis (coated aorta) as well as retroperitoneal fibrosis reminding of Ormond's disease. In this work we are presenting our collection of 83 images depicting these and many other interesting findings arranged into 17 pictures. Published here are images obtained by conventional radiography (CR), computed tomography (CT), magnetic resonance imaging (MRI), traditional bone scintigraphy, single photon emission computed tomography (SPECT) and also by means of positron emission tomography (PET) or hybrid PET/CT imaging if need be. In conclusion we underline the importance of whole-body PET/CT acquisition, including lower limbs, which depicts typical bilateral symmetric osteosclerosis of the long bones with diffusely increased radiopharmacon (fluorodeoxyglucose) uptake.