Myxoid
soft-tissue sarcomas represent a heterogeneous group of mesenchymal
tumors characterized by a predominantly myxoid matrix, including
myxoid liposarcoma (MLS), low-grade fibromyxoid
sarcoma (LGFMS),
extraskeletal myxoid chondrosarcoma (EMC), myxofibrosarcoma, myxoinflammatory fibroblastic
sarcoma (MIFS), and
myxoid dermatofibrosarcoma protuberans (DFSP). Cytogenetic and molecular genetic analyses have shown that many of these
sarcomas are characterized by recurrent
chromosomal translocations resulting in highly specific fusion genes (e.g., FUS-DDIT3 in MLS, FUS-CREB3L2 in LGFMS, EWSR1-NR4A3 in EMC, and COL1A1-
PDGFB in
myxoid DFSP). Moreover, recent molecular analysis has demonstrated a translocation t(1; 10)(p22; q24) resulting in transcriptional upregulation of FGF8 and NPM3 in MIFS. Most recently, the presence of
TGFBR3 and MGEA5 rearrangements has been identified in a subset of MIFS. These genetic alterations can be utilized as an adjunct in diagnostically challenging cases. In contrast, most myxofibrosarcomas have complex karyotypes lacking specific genetic alterations. This paper focuses on the cytogenetic and molecular genetic findings of myxoid
soft-tissue sarcomas as well as their clinicopathological characteristics.