Metastasis of myxoid liposarcoma to fat-bearing areas: A case report of unusual metastatic sites and a hypothesis.

Sarcoma is a rare disease that always metastasizes to the lungs and bones. Myxoid liposarcoma (MLPS), in comparison with other sarcomas, has a distinct biological characteristic. Recent studies have suggested that MLPS expresses high levels of adipophilin and chemokine (C-X-C motif) receptor 4 (CXCR4), which are correlated with adipogenesis and metastasis. In addition, the Ewing sarcoma breakpoint region 1-DNA damage-inducible transcript 3 (EWSR1-DDIT3) fusion transcript, recently identified in MLPS, was shown to selectively repress the osteoblastic transcription in multipotent mesenchymal cells. The present study reported a rare case of MLPS with metastasis in fat-bearing areas, including the bones, epidural region, orbits and abdominal cavity, while the lungs were not involved. Bone metastasis was diagnosed by magnetic resonance imaging and proven by histology. However, bone scanning lacked sufficient sensitivity to detect the bone metastasis. Based on these findings, we hypothesized that molecular adipophilin and molecular CXCR4 may contribute to the fat-bearing area metastasis pattern. Furthermore, the EWSR1-DDIT3 fusion transcript may repress the osteoblastic activity in the bone metastases, ultimately resulting in a low detection rate by bone scans.