[Malignant fibrous histiocytoma of the bone]

Five cases of malignant bone fibrous histiocytoma diagnosed by bioptic material are presented. The authors state that the diagnosis of these rare bone malignant neoplasms do not present a larger diagnostical problem. However, some differential diagnostic problems are often met compared to other bone neoplasms, especially in osteosarcoma, so in these cases are recommended that together with routine histologic examinations in establishment of diagnosis should be also used enzymohistochemical methods, especially alkaline and acid phosphatase. Also, it is necessary to use immunohistochemical methods with corresponding markers which the authors have used in establishment of diagnosis of their cases. Based on the analysis of the presented cases the authors support the theory of J. Brooks on the histogenesis of these tumours within his theory of differentiation of the mesenchimal tissue which is easily recognized in recidives and metastases of soft tissue sarcomas by phenotypes organized at the lower level of differentiation.