Diverse manifestations of ECD. (A) Coronal postcontrast chest computed tomography (CT) demonstrates extensive soft tissue sheathing of the thoracic aorta. (B) Enhancing lesions in the hypothalamic pituitary axis (HPA), brainstem, and cerebellar peduncle is shown in sagittal gadolinium enhanced T1 magnetic resonance imaging (MRI). (C) Three-dimensional fast imaging using steady-state acquisition (3D-FIESTA) MRI of the heart showing right atrial mass from ECD. (D) Maximal intensity projection (MIP) of ¹⁸F-fluoro-deoxyglucose (FDG)–positron emission tomography (PET) demonstrates typical hypermetabolic ECD lesions throughout the appendicular skeleton with greatest activity of the disease in the legs. (E) Irregular bilateral enhancing of ECD lesions in the middle cerebellar peduncles are demonstrated by postgadolinium axial T1 MRI. (F) Expansile irregularly enhancing ECD lesions in the pons seen on postgadolinium axial T1 MRI. (G) MIP of FDG-PET demonstrating ECD lesions with increased uptake in distal femur, orbit, multilevel thoracolumbar spine roots, and right atrium. (H) Periorbital xanthelasmas from ECD. (I-J) “Hairy kidney” hypermetabolic and contrast-enhancing perinephric infiltrates are shown on axial-fused FDG PET-CT and contrast-enhanced axial CT scan. (K) High-resolution axial CT scan image of the chest demonstrating reticulonodular opacities from ECD. (L) Atrophic or neurodegenerative changes in the brainstem and cerebellum are shown by axial T2-FLAIR MRI.