Primary biphasic synovial sarcoma of the breast: A case report and literature review

Retiz D.A.V.; del Rosario Cueva Pérez M.; Vela D.C. · Revista de Senologia y Patologia Mamaria (2026) · DOI: 10.1016/j.senol.2026.100778

Resumen

Introduction Synovial sarcoma is a rare malignant mesenchymal tumor, accounting for 5–10% of soft tissue sarcomas. Primary breast involvement is extremely uncommon, with very few cases reported. Case presentation A 37-year-old female presented with a progressively enlarging mass in the left breast over two years, with accelerated growth during pregnancy. Imaging revealed a BI-RADS 4C lesion. Core needle biopsy suggested a low-grade mesenchymal tumor. The patient underwent a total mastectomy, and final histopathology confirmed biphasic synovial sarcoma with negative margins. Seven months later, she developed local recurrence involving the chest wall and axillary region. She received chemotherapy with ifosfamide and docetaxel, followed by radiotherapy using IMRT/VMAT techniques. After two years of follow-up, she remains free of disease. Discussion Diagnosis is based on histopathological and immunohistochemical findings. Surgical resection is the mainstay of treatment, although recurrence is frequent and the role of adjuvant therapy remains controversial. Conclusion This case highlights the importance of multidisciplinary management in rare breast sarcomas.