Metastatic sclerosing epithelioid fibrosarcoma in an adult male from a tertiary care centre in India: a case report.

Background: Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare subtype of soft tissue sarcoma and the data from India is sparse. It is an unusual variant of fibrosarcoma that commonly arises in the soft tissues of the limb, head and neck, trunk and occasionally in the visceral organs and bones. This entity is commonly reported in the middle age group, men and women alike. Pathological clinchers include MUC 4 (Mucin 4, cell surface associated) positivity by immunohistochemistry, FUS-CREB3L1 fusion and EWSR1 rearrangement. This disease is notoriously known for its local recurrence and metastatic spread. Response to systemic therapy is poor and relapses are frequent. The role of targeted and immunotherapy is not well defined. Case presentation: Here we report a 46-year-old gentleman who presented to the Sarcoma Medical Oncology Clinic in our centre. He had primary involvement of right pubic bone with metastasis to liver, lung and diffuse lytic bony lesions. His diagnosis was reviewed multiple times before coming to final diagnosis of SEF. His molecular test for EWSR1 rearrangement was positive by fluorescence in-situ hybridisation. He did not respond to palliative doxorubicin, pazopanib and gemcitabine and docetaxel. Conclusion: Through this case report, we would like to highlight the rarity of this sarcoma, its classical pathological features, its close relationship to low-grade fibromyxoid sarcoma and the limited therapeutic options available. Hence, there is a need for further research in this entity.