IS case 474: Langerhans cell histiocytosis
Imaging Sciences URMC 2010
Publication Date: 2010-08-30
History
Patient is a 4-year-old male with right hip pain.
Findings
Pelvic radiograph demonstrated a well-defined lucent lesion without marginal sclerosis in the right femoral neck and intertrochanteric region. CT confirmed the presence of pathologic fracture and the absence of mineralized matrix. Fat saturated T2W MR showed very high signal intensity within the lesion. A similar lucent lesion was seen in the parietal skull.
Diagnosis
Discussion
Langerhans cells are antigen presenting dendritic cells normally found in the epidermis. Langerhans cell histiocytosis (LCH) is a general term for several diseases of abnormal Langerhans cell proliferation. These include acute and chronic disseminated forms (Letterer-Siwe and Hand-Schuller-Christian disease, respectively) and localized forms confined to either the lungs or skeleton (both referred to as eosinophilic granuloma (EG)). EG is an uncommon idiopathic disorder that can manifest as solitary or multifocal lytic bone lesions. Most cases are monostotic (50-75%). Common sites of involvement include the flat bones (skull, mandible, pelvis, scapula), ribs, spine, and femur.
The radiographic appearance is somewhat variable, however a lucent lesion without a sclerotic margin is the classic description. A permeative pattern of bone destruction may be seen, and sclerotic margins may appear during the healing phase. When LCH involves the spine, it may cause vertebral body collapse and so is part of the differential diagnosis for vertebra plana.
LCH characteristically has low signal on T1 weighted MR images and high signal on T2 images with marked enhancement following IV contrast administration.
Patients may present with localized or generalized constitutional symptoms. Most patients with skeletal EG are less than 30 years old, and the mean age at presentation is 5-10 years.
The differential diagnosis includes osteomyelitis, Ewing sarcoma, leukemia, and metastasis.
EG has a good prognosis, with frequent spontaneous remission. Treatment is generally conservative, except in cases with unresponsive symptoms or impending pathologic fracture where the treatment is surgical.
References
- David R, Oria RA, Kumar R, et al. Radiologic features of eosinophilic granuloma of bone. AJR Am J Roentgenol. 1989 Nov;153(5):1021-6. PMID: 2801420
- Fisher AJ, Reinus WR, Friedland JA, Wilson AJ. Quantitative analysis of the plain radiographic appearance of eosinophilic granuloma. Invest Radiol. 1995 Aug;30(8):466-73. PMID: 8557512
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