Histiocytosis X. II. Histologic appearance correlated to prognosis and extent of disease.

Specimens from 27 bone lesions of histiocytosis X were analysed semiquantitatively before treatment. Eosinophilic granulocytes seemed to be the only significant prognostic cell type. Absence of eosionphils or only slight eosinophilia in the initial bone lesions were found predominantly in widespread disease with fatal outcome. A moderate or severe degree of eosinophilia dominated in solitary bone lesions with good prognosis.