Correlation of lipid content and composition with liposarcoma histology and grade.

Abstract

The determination of sarcoma grade, histologic type, and differentiation is often pathologist dependent and requires considerable expertise. Lipid content and composition was analyzed in ex vivo fat, lipoma, and liposarcoma tissue samples using proton-decoupled 13C nuclear magnetic resonance (13C-NMR) spectroscopy and correlated with the histologic type and grade of liposarcoma. The well-differentiated liposarcomas were found to have threefold increases in fatty acyl chain content compared with benign lipomas. The fatty acyl chain content of the dedifferentiated and pleomorphic liposarcomas was 1% of that found in lipoma and < 0.2% of that found in well-differentiated liposarcoma. The 2.1- to 2.8-fold increase in the degree of polyunsaturation in the dedifferentiated and pleomorphic liposarcomas compared with well-differentiated liposarcoma could largely be accounted for by the 2.3-fold increase in the percentage of fatty acyl chains of lipid containing linoleic acid. The dedifferentiated and pleomorphic liposarcomas contained both free fatty acids and phospholipids that were not NMR detectable in normal fat, lipoma, and well-differentiated liposarcoma. Ex vivo 13C-NMR spectroscopy may be used to distinguish lipoma from well-differentiated, dedifferentiated, and pleomorphic liposarcoma based on changes in lipid and phospholipid metabolite profiles and may serve as adjunct to conventional light microscopy for the determination of liposarcoma histologic type and thus grade.