OBJECTIVE: To retrospectively assess the association of mediastinal, cardiovascular and pleuropulmonary findings on chest CT of 40 patients with immunohistochemically and histologically proven Erdheim-Chester disease (ECD). METHODS: The multidetector chest CT images of 40 ECD patients were reviewed in consensus by chest and cardiovascular radiologists. RESULTS: Thirty-four (85%) patients had periaortic infiltration that extended around the aortic branches of 29 (73%). Perivascular infiltration extended into the cardiac sulci in 22 (55%) (p < 0.005). Infiltration involved the right atrium wall in 12 patients, associated with severe narrowing of the atrial lumen in 8. Pericardial effusion and/or thickening were observed in 24 (60%) patients. Lung involvement, seen in 22 (55%) patients, was associated with mediastinal infiltration (20; p < 0.005) and pleural thickening or effusion (16; p = 0.001); it consisted of smooth interlobular septa (21), subpleural thickening (13), poorly defined centrilobular nodular opacities (9), ground-glass opacities (8) and/or lung cysts (5). CONCLUSION: The detailed description of thoracic ECD involvement seen in these patients showed that infiltration into the mediastinal spaces including the pericardium, coronary sulci and right atrium is frequently associated with pleural and interstitial lung diseases.