Eosinophilic granuloma of bone.

Forty-three patients with histologically proven Histiocytosis X localized to bone at presentation have been reviewed. Thirty-six patients presented with solitary bone lesions and 31 have healed without complication with a mean follow-up of 10 years. The remaining five patients developed polyostotic disease, three exhibiting either pulmonary lesions or diabetes insipidus. Seven patients presented with multiple bone lesions and six of them developed other bone lesions. Four of these patients also showed some of the features of Hand-Schüller-Christian disease. An increase in size of the presenting bone lesion within a few months of biopsy heralded the subsequent development of further bone or soft tissue lesions and was the only feature of prognostic value.