Clinicopathologic Prognostic Factors in Myxoid Liposarcoma: A Retrospective Study of 49 Patients With Long-Term Follow-Up

BACKGROUND: The main goal of this retrospective study was to investigate prognostic factors influencing the survival of myxoid liposarcoma (MLS) with emphasis on the role of transitional areas (TLS) and round cell morphology (RCLS). METHODS: From 1977 to 2004, 49 patients-28 men (57%) and 21 women (43%) with a median age of 44 years (range, 7-83 years)-were diagnosed with an MLS. In 42 patients, the histology could be reviewed, and tumors were classified as MLS, TLS, or RCLS. Clinicopathologic factors were analyzed for influence on survival by univariate and multivariate methods. RESULTS: The median follow-up of 49 patients was 101 months (range, 4-550 months). Of the 42 patients for whom histology was reviewed, 16 tumors were classified as MLS (38%), 19 as TLS (45%), and 7 as RCLS (17%). Sixteen patients (33%) developed a local recurrence after a median follow-up of 21 months (range, 2-108 months). Thirteen patients (27%) developed metastases. The median interval between diagnosis and metastasis was 41 months (range, 0-222 months). Median survival after metastasis was 18 months (range, 1-179 months). The 5- and 10-year disease-specific survival rates were 85% and 72%, whereas the 5- and 10-year overall survival rates were 83% and 68%, respectively. Age at presentation (P = .02), tumor grade (P = .01), and tumor size (P = .005) were significant prognostic factors associated with survival. Tumor grade was the only independent prognostic variable that remained significant with multivariate analysis. A TLS presentation had no negative influence on patient survival. CONCLUSIONS: Age at presentation, tumor grade, and tumor size had a negative influence on survival by univariate analysis, whereas tumor grade was the only independent prognostic factor by multivariate analysis. TLS was not associated with poor outcome.