Primary High-Grade Myxoid Liposarcoma of the Extremities: Prognostic Factors and Metastatic Pattern

SIMPLE SUMMARY: Around 12–25% of patients with high-grade myxoid liposarcoma (MLS) develop local relapses and 30–60% develop pulmonary or extrapulmonary metastases over a 10-year follow-up period. The aim of this study was to evaluate factors that may influence overall survival (OS), local recurrence-free survival (LRFS), metastasis-free survival (MFS), post-relapse survival (PRS), and disease-free survival (DFS) in a select series of localized, deep-seated, high-grade myxoid liposarcomas of the extremities. The tumor sites and surgical margins were not found to be significant risk factors for OS, LRFS, MFS, PRS, and DFS in this study, confirming that patients with tumors in the extremities have a more favorable prognosis. Additionally, we concluded that tumor size is a significant risk factor for MFS and DFS. ABSTRACT: (1) Background: This retrospective study aimed to analyze the history and treatment outcomes of localized, high-grade MLS of the extremities. (2) Methods: We retrospectively reviewed 82 patients with primary high-grade MLS of the extremities. OS, LRFS, MFS, PRS, and DFS were analyzed. (3) Results: Five-year OS and LRS were 96% (95% CI: 86–98) and 94% (95% CI: 85–98), respectively. Statistical analysis indicated no risk factors for OS and LFRS. MFS was 77% (65–85) at 5-year follow-up. Size (p = 0.0337) was the only risk factor statistically significant for MFS (HR = 0.248, 95% CI: 0.07–0.84). Median PRS after distant metastasis was 34 months (range: 1–127 months). Five-year PRS was 79% (48–93). Overall, the 5-year DFS was 76% (65–85). (4) Conclusions: Patients with MLS were found to have a good prognosis. In high-grade deep-seated tumors, common risk factors for MLS do not correlate with survival. Tumor size appears to be the only predictor of long-term DSF and MSF.