Eosinophilic granuloma is the localized form of histiocytosis X.
Diagnosis The peak age of onset is between 1 and 3 years of age. This tumor has been described as the “great imitator” of bone tumors. Lesions are painful and are most often confused with osteomyelitis or sometimes Ewing sarcoma. Lesions often appear “punched out” on conventional radiographs, but sometimes elicit periosteal reactions, suggesting a sarcoma. The child may have a low-grade fever and elevated ESR and CRP, making the differentiation from an infection difficult. Consider ordering skull films because the skull is the most common site of bony involvement. Sometimes the diagnosis must be established by biopsy.
Management The natural history is of spontaneous resolution over a period of many months. Management options include simple observation, immobilization to improve comfort and reduce the risk of pathologic fracture, injection with steroid, limited curettage, or radiation treatment.
Spine lesions cause collapse (vertebra plana) and sometimes neurologic involvement. Manage by observation or brace immobilization. Rarely, curettage is necessary to hasten resolution.
Lower limb long-bone lesions, if large enough, may pose a risk of pathologic fracture. Curettage and cast protection may be appropriate.
Giant Cell Tumors
Giant cell tumors (GCT) are aggressive tumors that occasionally occur in adolescents. Lesions are usually metaphyseal or epiphyseal, eccentric, expansive, and show little sclerosis or periosteal reaction. These tumors are locally invasive and often recur. Manage by curettage, thermoablation and grafting. Provide careful follow-up because recurrence develops in about a quarter of cases.
Neurofibromatosis causes widespread pathology, including scoliosis, pseudoarthrosis of long bones, thoracic lordoscoliosis, protrusio acetabuli, and abnormal bone growth.
This is often present in the vertebrae or skull but may appear in the extremities. Lesions are diffuse and suggest a malignant tumor. Wide resection is necessary, and recurrence is common.