[The pathology of soft tissue sarcomas]

Soft tissue sarcomas are rare and can cause considerable difficulty in diagnosis and differential diagnosis as well as in estimation of the prognosis. These problems are due in part to the wide histological diversity, which is a consequence of intratumoral heterogeneity. The best known example of a very heterogeneous soft tissue tumor is malignant fibrous histiocytoma (MFH). Regular application of ancillary techniques, including electron microscopy and immunohistochemistry, has made it possible to reduce the number of unclassified cases from more than 10% to about 5%. Further progress in this direction is to be expected from cytogenetic studies, since for some of the tumor types characteristic chromosomal abnormalities have been established. Prognosis has been related to the grade of malignancy, but recent studies show that in many soft tissue sarcomas it will also be possible to correlate prognosis with DNA ploidy. By contrast, overexpression of the multidrug resistance gene mdr-1 does not seem to play an essential role in soft tissue sarcomas.