Cytogenetic and molecular cytogenetic findings in giant dedifferentiated liposarcoma of the thigh.

[dedifferentiated liposarcoma]

Non-retroperitoneal dedifferentiated liposarcoma (DDLS ) is relatively uncommon and its characterization at the molecular genetic level has been limited . We describe the cyto-genetic and molecular cytogenetic findings of giant DDLS arising in the right thigh of an 83 -year -old woman . Magnetic resonance imaging revealed a mass composed of two components with heterogeneous signal intensities , suggesting the coexistence of a fatty area and another soft tissue component . A wide resection of the tumor was performed . The resected , grossly heterogeneous mass , measuring 26 x 18 x 8 cm , was histopathologically composed of a well-differentiated liposarcomatous component transitioning abruptly into a dedifferentiated one . Cytogenetic analysis exhibited a complex karyotype with several numerical and structural alterations , including ring and giant marker chromosomes . Metaphase-based comparative genomic hybridization analysis showed high -level amplifications of 1 q 21 -q 25 and 12 q 13 -q 21 . Interphase fluorescence in situ hybridization analysis revealed MDM 2 and CDK 4 gene amplification in both the well-differentiated and dedifferentiated components . These findings indicate that DDLS of the extremity shares a similar genetic background to retroperitoneal DDLS .