Unifocal LCH (Eosinophilic Granuloma)
Langerhans cell histiocytosis (LCH) may be unisystem (unifocal or multifocal lesions) or multisystem disease.
Unifocal LCH occurs in older children or adults who usually present with a solitary bone lesion (previously called eosinophilic granuloma). The lytic process begins within the medullary cavity and erodes through the cortex to involve adjacent soft tissues. Bone lesions may be initially asymptomatic but eventually cause pain, tenderness, or pathologic fracture.
The most frequently involved bones are the skull, femur, vertebra, pelvis, and ribs. Less commonly, unifocal LCH presents as lymphadenopathy or as a soft tissue mass or nodule at sites like skin, lungs, stomach, brain, thyroid, thymus, or oral cavity. Unifocal LCH is indolent and may regress spontaneously or be cured by local excision or curettage. It has excellent prognosis.
Slide courtesy of Piero Picci, M.D., Director, Laboratory of Experimental Oncology, Instituto Ortopedico Rizzoli, Bologna, Italy. Used with permission.