Langerhans Cell Histiocytosis

Eosinophilic Granuloma, Histiocytosis X

CLINICAL SUMMARY

Langerhans cell histiocytosis presents as a painful lytic bone lesion in children. It is most commonly monostotic, in which case it is also termed eosinophilic granuloma and follows a benign course. Treatment is curettage (intralesional excision) or steroid injection. Disseminated variants can demonstrate visceral involvement and behave more aggressively.

DIAGNOSTIC FEATURES

History	Children and young patients, 1 to 15 years of age Localized aching pain Pain can be worse at night Infrequently, low-grade fevers
Location	When in long bones, diaphyseal, medullary Distribution: 70% involve skull, jaw, spine, pelvis, and ribs
Margins	Geographic lysis No soft tissue mass Thick, nonstriated periosteal reaction
Matrix	No mineralized matrix

IMAGING

Langerhans cell histiocytosis can mimic infection, sarcoma, or lymphoma.
Langerhans cell histiocytosis appearing as a lytic lesion, centrally located in the diaphyseal femur. A thick periosteal reaction implies an indolent process, despite a wide zone of transition ( left ).
Bone scan shows a corresponding region of radiotracer uptake. The uptake is sometimes less prominent than radiographs would predict ( right ).