[Histiocytosis X: radiologic evaluation of 52 patients].

Fifty-two patients with histologically proven histiocytosis X and intrathoracic and/or bone lesions have been evaluated. In the group, bone lesions appear clearly prevalent (51/52 patients) mainly as localized monostotic disease (31/51). Flat bones were more frequently involved, with special evidence for skull and ribs. Short as well as long bones were only seldom compromised, almost only in polyostotic and generalized disease. On the basis of our experience the most suggestive radiological findings in bone to diagnose an histiocytosis X were the following: preferential involvement of a flat bone, osteolytic pattern, sharp borders (72.9%), rare evidence of pathological fracture (20%) and periostitis (10%). On the contrary, the involvement of the neighbouring soft tissues (38.8%) appears to be significant.