Age / Sex : 6 / M

Chief complaint : left thigh pain, fever

What is your impression?
Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy of You Seon Song, Pusan National University Hospital   

Discussion

Answer:  Langerhans cell histiocytosis

Findings:

Linear periosteal reaction at proximal diaphysis of the left femur on initial radiograph.

Intramedullary mass with lamellated periosteal reaction and extensive perilesional edema on T2WI.

Focal cortical disruption on T1WI.

Osteolytic intramedullary mass with bone destruction, rapid progression on follow-up radiography after 1 week.

Expansile intramedullary mass with cortical destruction and extensive perilesional edema on follow-up MRI

Differential Diagnosis:

 Osteomyelitis, Ewing’s sarcoma, lymphoma

Discussion:

 Bone lesions are the most common radiographic manifestations of LCH(80%), and it has a predilection for the flat bones such as skull.

Long bone involvement is more common in children than in adults, and the femur, humerus, tibia are the most commonly involved long bones and lesions typically occurs in the diaphysis or metaphysis.

Early lesions show lytic, expansile, and aggressive ness, but less aggressive features such as cortical thickening and smooth periosteal reaction may be seen.

CT and MRI imaging findings are intramedullary lesions with extramedullary soft tissue components that have T1 low-, T2 high signal intensity.

Fever and elevated ESR levels are common in LCH, Ewing sarcoma and non-Hodgkin lymphoma of bone.

References:

1. J Zaveri, Q La, G Yarmish et al. More than just Langerhans cell histiocytosis: A radiologic review of histiocytic disorders. Radiographics 2014;34:2008-2024


2. Meyer JS, Harty MP, Mahboubi S, et al. Langerhans cell histiocytosis: presentation and evolution of radiologic findings with clinical correlation. RadioGraphics 1995;15(5):1135–1146


3. Paul Guillerman. Osteomyelitis and beyond ; Pediatr Radiol (2013) 43 (Suppl 1):S193–S203