Dedifferentiated liposarcoma with abrupt transition of low-grade and high-grade dedifferentiation: A rare case report

Figure 1.. MRI images of DDLPS. Axial fat-saturated T2-weighted image (a) and coronal T2-weighted image (b) show a relatively well-defined pure fatty mass (white arrows), surrounding a non-fatty solid mass. DDLPS: dedifferentiated liposarcoma; MRI: magnetic resonance imaging.

Figure 2.. Gross appearance of DDLPS. The cross section of the WDLPS reveals yellow tissue, the high-grade DDLPS is fish flesh-colored, and the middle necrotic area is pale yellow; the low-grade DDLPS (white arrows) is gray-white, but the local area is grayish-brown. DDLPS: dedifferentiated liposarcoma; WDLPS: well-differentiated liposarcoma.

Figure 3.. Histologic analysis of dedifferentiated liposarcoma specimens. (a) Typical well-differentiated liposarcoma of the adipocytic/lipoma-like type (hematoxylin–eosin stain; ×100). (b) High-grade dedifferentiated liposarcoma demonstrates high cellularity, pleomorphism, and marked cellular atypia (hematoxylin–eosin stain; ×100). (c) and (d) Transition from low-grade dedifferentiation with inflammatory myofibroblastic tumor-like features to high-grade dedifferentiation with undifferentiated pleomorphic sarcoma features (hematoxylin–eosin stain; c ×40). The boundary (white arrows) between them is clear (hematoxylin–eosin stain; d ×20). (e) and (f) Transition from low-grade dedifferentiation with fibromatosis-like features to high-grade dedifferentiation with undifferentiated pleomorphic sarcoma features (hematoxylin–eosin stain; e×40). The boundary (white arrows) between them is clear (hematoxylin–eosin stain; f ×20).

Figure 4.. Fluorescence in situ hybridization of the MDM2 gene. FISH analysis confirmed MDM2 gene amplification (clustering of red signals) in the nuclei of atypical cells. FISH: fluorescence in situ hybridization.