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

摘要

Non-retroperitoneal dedifferentiated liposarcoma (DDLS) is relatively uncommon and its characterization at the molecular genetic level has been limited. We describe the cytogenetic 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 26x18x8 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 1q21-q25 and 12q13-q21. Interphase fluorescence in situ hybridization analysis revealed MDM2 and CDK4 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.