Recent developments in soft tissue tumors.

Abstract

The field of soft tissue tumor pathology, despite the relative rarity of the lesions concerned, has grown considerably in recent years and has featured very prominently in the academic pathology literature. This stems from the facts that increasing diagnostic sophistication has allowed the continued refinement of classification schemes and the delineation of numerous previously unrecognized 'entities' and that the application of modern cytogenetic and molecular genetic techniques has revealed the remarkable importance of reproducible cytogenetic aberrations in our understanding of the pathobiology of this group of neoplasms. This presentation will aim to summarize data regarding some of the recently characterized entities as well as the major molecular genetic advances. Newly characterized 'entities' which are important because of the ease with which they are confused with lesions of very different biologic potential include chondroid lipoma, pleomorphic hyalinising angiectatic tumor, extrapleural solitary fibrous tumor, giant cell angiofibroma, cellular angiofibroma, retiform hemangioendothelioma, composite hemangioendothelioma and low grade fibromyxoid sarcoma. The 'hemangioendotheliomas' also represent an important area of conceptual evolution as we begin to more critically analyze the concept of borderline malignancy. Concerning molecular genetic advances, the most striking data to emerge are the frequency of tumour-specific reciprocal translocations, the frequency of biologically revealing cytogenetic aberrations in benign lesions and the emerging evidence of striking differences in cell cycle abnormalities in the different sarcoma types.