Bone involvement in Erdheim-Chester disease: imaging findings including periostitis and partial epiphyseal involvement.

Purpose: To retrospectively review the bone findings at radiography, scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging in 11 patients with immunohistochemical and histologic proof of Erdheim-Chester disease.
Materials and Methods: This study was designed as a retrospective review; approval of the institutional review board and patient consent were not required for this type of study. Eleven patients (eight men and three women; mean age, 49 years; range, 17-68 years) with Erdheim-Chester disease underwent conventional radiography of the skeleton and bone scintigraphy. Two patients underwent CT of the femora and 10 underwent CT of the skull. Eight patients underwent MR imaging. Conventional radiographs, bone scintigrams, CT scans, and MR images were reviewed in consensus by four musculoskeletal radiologists.
Results: All 11 patients had involvement of the long bones and normal axial skeleton, hands, and feet. Bilateral and symmetric osteosclerosis of the diaphysis of the long bones was present in 52 (26 pairs) (98%) of the 53 bone lesions visible on conventional radiographs. Osteosclerosis was heterogeneous in 65% of the patients and homogeneous in 35%. Diaphysis was involved in 100% and metaphysis in 44 (83%) lesions. Partial epiphyseal involvement sparing the subchondral bone was present in 24 (45%) lesions. Periostitis was seen in 35 (66%) and endosteitis in 50 (94%) of the 53 long bones involved. Bone scintigraphy depicted tracer uptake in all bone lesions visible on radiographs. Skull and face bone lesions were present in two patients. MR imaging depicted a replacement of the normal fatty bone marrow by heterogeneous signal intensity on T1- and T2-weighted spin-echo images. Lesion extent, epiphyseal involvement, and periostitis were clearly depicted at MR imaging.
Conclusion: This series provides a detailed description of bone involvement in Erdheim-Chester disease. Periostitis and partial epiphyseal involvement of the long bones are also features of this disease. (c) RSNA, 2005.
((c) RSNA, 2005)