Low-grade fibromyxoid sarcoma (LGFMS) and sclerosing epithelioid fibrosarcoma (SEF) are ultra-rare soft tissue sarcomas with limited clinical data and no prospective studies to date. These tumors pose unique challenges due to their rarity, heterogeneous behavior, and the absence of established therapeutic standards.

Building on two international retrospective studies already conducted within the PUSH consortium, this working group is establishing a large, international prospective observational study—including a translational research component—to better define the natural history, molecular characteristics, and treatment outcomes of LGFMS, SEF, and hybrid LGFMS/SEF. The findings will help identify predictors of therapeutic response and guide future clinical practice.

Our Objectives
LGFMS/SEF Working Group aims to create a cooperative, international, and multidisciplinary team of disease experts to advance research and improve treatment for this ultra-rare sarcoma subtype. The LGFMS/SEF study will serve as a model for future prospective studies of other ultra-rare sarcomas within the PUSH Platform.

Our Core Initiatives

• Establish an international, prospective observational study to build on prior retrospective findings.


• Develop a multinational database for LGFMS, SEF, and hybrid tumors as a foundational PUSH study.


• Define translational research components in collaboration with the Translational Working Group.


• Engage patient advocates to strengthen community participation and representation.