Imaging spectrum of Erdheim–Chester disease—An extended report of two cases

Erdheim–Chester disease (ECD) is a rare sporadic systemic histiocytic disease of unknown etiology that affects multiple organ systems. We report two cases of ECD with musculoskeletal, orbital/periorbital involvement with dural and sellar mass lesions. Case 1 showed the unusual feature of ECD with pituitary mass and both anterior and posterior pituitary hypofunction. Proton magnetic resonance spectroscopy (1H MRS) was attempted from the orbital mass in case 2 by placing a voxel, in the orbital mass which showed isolated lipid resonance at 1.3 ppm that can be attributed to the presence of lipid-laden foamy macrophages seen in this condition. Application of 1H MRS in orbital lesions is unique to the present report. The magnetic resonance imaging (MRI) of brain and orbit including proton magnetic resonance spectroscopy (1H MRS) findings are discussed with a short review of the available literature.