Abstract. 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.
IntroductionLiposarcoma (LPS) contains three subtypes: i) Well-differentiated LPS and dedifferentiated LPS; ii) myxoid LPS (MLPS); and iii) pleomorphic LPS. MLPS accounts for ~30% of all LPS cases and is characterized by the appearance of uniform, round-to oval-shaped cells with myxoid stroma (1,2). For local disease, the 5-year disease-specific survival (DSS) rate is 93%. By multivariate analysis, an age of >45 years, the male gender and locally recurrent disease are predictive of a poor 5-year DSS rate. For metastatic disease, the outcome is poor, with a 5-year DSS rate of 8.2%. In comparison with other sarcomas, MLPS often metastasizes to the abdomen (49%), rather than the lungs (14%) and bones (23%) (3). Understanding the metastasis pattern and underlying mechanism should aid in improving the survival of patients with this disease.The current study presents a rare case of MLPS with multiple metastases in fat-bearing areas, but no involvement of the lungs. Unexpectedly, the presence of bone metastasis as diagnosed by magnetic resonance imaging (MRI) and proven by histology, was negative on bone scans. Written informed consent was obtained from the patient's family.
Case reportA 53-year-old male presented with a slowly enlarging mass in the right thigh in May 2008. The patient underwent a local excision at Shanghai General Hospital (Shanghai, China). and the histology revealed a diagnosis of MLPS. The patient subsequently received adjuvant radiotherapy (details unknown) and was free from recurrence for 34 months after the resection. The patient presented to The Sixth People's Hospital of Shanghai Jiao Tong University (Shanghai, China) on April 26, 2011, with lower back pain that radiated to the bilateral thighs for more than one month. Bone scans sh...