[Localizations of histiocytosis X in bone]

Histiocytosis X is still of unknown origin. Its clinical patterns are various and it is above all a bone disease of children, mostly boys. It is a tumoral condition basically benign but with a strong tendency toward dissemination and destruction. Its natural history is unpredictable. The authors have reviewed 37 cases after a 44 months mean follow-up for bringing up a better understanding of the role of orthopedic surgery. The diagnosis was always based on biopsies looking for at least two basic signs out of four possible ones. Scintigraphy was used to detect other locations. MRI was used to evaluate the effect of treatment. In single eosinophilic granuloma, curettage was associated with biopsy. Local injections of corticoids may help in spinal locations. In disseminated forms, surgical treatment should be little aggressive, limited to a biopsy of the most superficial lesion. These forms should be treated by radiotherapy corticotherapy and chemotherapy, as well as the aggressive lesions, the extensive ones, the threatening ones and those which are not accessible.