Histyocitic Tumors of the Soft Tissues

Abstract

Tumors of the soft tissues are very various; they reproduce only partly the characteristics of the tissues of origin and present many modulations due principally to the stage of differentiation. The definition of these lesions must be precise as the different groups have quite unlike behavior and require an appropriate treatment. They are usually classified as tumor-like lesions, benign neoplasms, malignant neoplasms. This classification, however, is not sufficient for a precise prognostic and theraphy as there are behaviour anomalies, such as tumors which grow by infiltration and do not metastasize and encapsulated tumors which develop metastases. For instance, every mesenchymal tumor grows into the skin by infiltration but only few of them produce metastasis; some fibromatosis are true neoplasms which may display insidious infiltrative growth and frequently recurrence appears after the removal but there are no metastases. Sarcomas of varying histological types may have a different behavior requiring a different form of treatment. New knowledge on tumors of the soft tissues is due essentially to the combination of research by «in vitro» culture and clinical-pathological studies. The demonstration of the histogenesis of some tumors allowed the reclassification of fibrous growth deriving from facultative fibroblastic cells. These tumors are composed of fibroblasts with a xanthomatous component, giant cells and phagocytic foam cells: histogenetically they are histiocytic fibroblasts. Istiocytes may behave as fibroblasts or fagocytes and sometimes they assume the two appearances in a same tumor. Among these tumors the so called protuberans fibrosarcomas, the sclerosing hemangiomas, many giant cell tumors, and the fibrous xanthomas must be considered as histiocytic tumors or fibrous histiocytomas. The malignant counterpart of fibrohistiocytomas, that is the malignant xanthofibroma, the malignant histiocytoma and the rare malignant protuberans fibrosarcoma, should be recognized.