Original ArticlesPrognostic Value of Myogenic Differentiation in Dedifferentiated LiposarcomaKurzawa, Pawel MD, PhD*,†; Mullen, John T. MD‡; Chen, Yen-Lin MD§; Johnstone, Sarah E. MD, PhD∥; Deshpande, Vikram MBBS∥; Chebib, Ivan MD∥; Nielsen, G.P. MD∥Author Information *Department of Clinical Pathology, Poznań University of Medical Sciences †Pathology Department, University Hospital of Lord’s Transfiguration, Partner of Karol Marcinkowski University of Medical Sciences, Poznań, Poland Departments of ‡Surgery §Department of Radiation Oncology ∥James Homer Wright Pathology Laboratories, Massachusetts General Hospital and Harvard Medical School, Boston, MA I.C. and G.P.N. are cosenior authors. The content is solely the responsibility of the authors and does not necessarily represent the official views of Harvard Catalyst, Harvard University, and its affiliated academic health care centers, or the National Institutes of Health. Conflicts of Interest and Source of Funding: This work was conducted with support from Harvard Catalyst, The Harvard Clinical and Translational Science Center (National Center for Advancing Translational Sciences, National Institutes of Health Award UL 1TR002541) and financial contributions from Harvard University and its affiliated academic health care centers. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Ivan Chebib, MD, James Homer Wright Pathology Laboratories, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114 (e-mail: [email protected]). The American Journal of Surgical Pathology: June 2020 - Volume 44 - Issue 6 - p 799-804 doi: 10.1097/PAS.0000000000001436 Buy Metrics Abstract Myogenic differentiation (MD) has been claimed to be a poor prognostic factor in dedifferentiated liposarcoma (DDLPS). To validate this, the prognostic significance of MD in a uniformly treated cohort of DDLPS was assessed. A cohort of patients that have been uniformly treated at one institution for DDLPS of the retroperitoneum and pelvis were stained with smooth muscle actin (SMA) and desmin and semiquantitatively scored for staining focality and strength. Clinical and survival data was collected, and the prognostic significance of MD was evaluated. A total of 50 patients with uniformly treated DDLPS were evaluated. SMA (P=0.052) and a combined score of MD (SMA+desmin) showed a statistically significant decrease in 5-year disease-free survival (P=0.002) in univariate analysis and in multivariate testing combined MD trended toward significance (P=0.052). Combined MD was associated with a decreased OS in multivariate analysis (P=0.004). In a uniformly treated cohort of DDLPS stained for myogenic markers, a combined myogenic score was associated with poor overall survival in multivariate analysis. However, the difference in groups was slight and the clinical application is limited. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.