Abstract
Soft tissue myoepithelial carcinoma (MEC) is an extremely rare mesenchymal tumor that has a poor prognosis unless complete surgical resection is achieved. The present study reported a case of a 38-year-old woman with a tumor in the left paraspinal region at L2 to L3 with vertebral destruction. MEC was diagnosed based on molecular pathological examination of a biopsy specimen. Because curative surgery was expected to be difficult, a combination of chemotherapy with doxorubicin and ifosfamide and proton beam therapy as local therapy was performed, resulting in long-term survival for at least 7.8 years. To the best of our knowledge, this is the first case of soft tissue MEC for which classical cytotoxic chemotherapy and proton beam therapy were effective. Although surgical resection with negative margins is the mainstay of treatment for MEC, adequate doxorubicin-based systemic therapy and high-dose radiation therapy may be a feasible alternative in patients with unresectable or advanced MEC. Future studies on the relationship between molecular pathological features, including biomarkers, and the selection of therapeutic agents are warranted.