General description

Erdheim-Chester disease (ECD) is a relatively rare form of non-Langerhans cell histiocytosis characterized by the abnormal proliferation of non-Langerhans cell histiocytes. These histiocytes infiltrate various body systems, leading to distinctive clinical manifestations. A hallmark of ECD is symmetric bilateral bony sclerosis predominantly affecting the long bones. The disease also extends its infiltration to the central nervous system (diabetes inspidus), cardiovascular system, lungs (manifesting as interstitial pneumonia), kidneys, and skin, where it can cause xanthoma palpebrarum.

Radiographic features

Hypothalamus-pituitary axis

In the central nervous system, a lobulated mass extending from the hypothalamus to the pituitary gland is sometimes reported, which can lead to generalized hypopituitarism. Notably, diabetes insipidus specifically affects the posterior pituitary, typically causing a loss of the characteristic hyperintensity seen on T1WI in this region.

Brainstem and cerebellar lesion

T2WI and FLAIR shows bilateral hyperintensity in the pons and dentate nuclei.

Meningeal lesion

In Erdheim-Chester disease, meningeal lesions typically present as dural thickening or a dural mass. On T2WI, these lesions typically exhibit iso- to hypointensity, and there is homogeneous enhancement of these lesions on T1WI.

Perivascular mass

In Erdheim-Chester disease, an abnormal contrast-enhanced mass surrounding the vasculature is reported. This can be observed as concentric soft tissue encasement of arteries, causing stenosis and a decrease in the blood flow signal of peripheral arteries.