Imaging Diagnosis and Differential Diagnosis of Clavicular Langerhans Histiocytosis

Objective: To summarize the imaging findings of langerhans histiocytosis (LCH) of the clavicle. Materials and methods: Preoperative X-ray, CT and MRI data of 9 cases (male and female ratio 4: 5, average age 10.5 years) of clavicular LCH confirmed by surgery and pathology from July 2005 to December 2018 were collected for retrospective analysis. Results: There were 4 cases in the middle clavicle, 2 cases in the outer 1/3 of the clavicle, and 3 cases in the inner 1/3 or middle 2/3 of the clavicle. 6 cases showed pure osteolytic bone destruction, cortical fracture, reactive hyperplasia and lamellar callus at the edge of the damaged area. One case presented with insect-etched bone destruction with indistinct distension and blurred boundary. In 2 cases, the lesions showed expansible growth with multiple bone septa, intact bone capsule and no surrounding soft tissue mass. In 4 cases, the lesions presented uneven low signal on T₁WI, uneven high signal on T₂WI, and moderate uneven enhancement on enhanced scan. Conclusion: LCH of clavicle is common in children, and the imaging manifestations of different stages and different parts of clavicle are different, which should be differentiated from ewing's sarcoma, chronic osteomyelitis, plasma cell myeloma and other diseases.