Coloured 3D computed tomography (CT) angiogram scan of the aorta of a 61 year old male patient with Erdheim-Chester disease (ECD). ECD is a rare blood cancer caused by the abnormal proliferation of histiocyte white blood cells. Accumulation and infiltration of the histiocytes into different tissues causes inflammation and damage. Here, inflammation of the celiac artery has lead to its stenosis (narrowing). Treatments for ECD include chemotherapy and immunotherapy, although the prognosis is poor.