Liposarcomas

Abstract

A series of atypical [human] lipomas, well-differentiated/dedifferentiated liposarcomas, and myxoid/round cell liposarcomas were examined by light microscopy and EM to better understand the marked variation in histologic growth patterns exhibited by adipose tissue neoplasms. They were composed of a mixture of adipocytes and nonfat-storing mesenchymal cells or were predominantly made up of only 1 of these cell types. From these and other published observations, it was assumed that myxoid/round cell liposarcomas are composed of adipocytes; spindle cell lipomas, atypical lipomas and well-differentiated liposarcomas are composed of a mixture of the 2 cell types; and the dedifferentiated regions of well-differentiated liposarcomas are composed of nonfat-storing mesenchymal cells. The basic structural differences of the 2 cell types and the quantitative variations when they occur in mixtures seem to account for the marked variations in neoplastic growth patterns.