Characteristics and radiological features of bone lesions in patients with Langerhans cell histiocytosis: A case series study.

The aim of this study was to explore the characteristics and radiological features of bone lesions in patients with Langerhans cell histiocytosis (LCH). This case series study included patients with LCH in the Second Affiliated Hospital Zhejiang University School of Medicine between January 2010 and December 2020. A total of 126 patients with 141 lesions were included. Among the 141 lesions, craniofacial bones (n = 24, 17.02%), trunk bones (n = 40, 28.37%), limb bones (n = 41, 29.08%), and vertebrae (n = 36, 25.53%) were the most frequently affected anatomic sites. X-ray showed 84 (84/110) bone osteolytic lesions were in the bone marrow cavity or cancellous. Computed tomography (CT) showed 17 (17/141) lesions with unclear boundaries. Magnetic resonance imaging found 48 (48/127) lesions with heterogeneous hyperintense signals. The radioactive concentration was observed in 97 (97/113) cases, multiple lesions were observed in 8 (8/113) cases, and a total of 106 lesions were checked out by single-photon emission CT. Positron emission tomography-computed tomography (PET-CT) found that 21 lesions of PET-CT were positive and single. The bone lesions of LCH are observed in limb bones, trunk bones, and vertebrae. The radiological features of bone lesions in patients with LCH are complex and varied. A combination of X-ray, CT, magnetic resonance imaging, single-photon emission CT, and PET-CT might be needed for complete detection and characterization of the lesions.