Long-term Efficacy of Eribulin in Patients with Advanced Myxoid Liposarcoma Resistant to Trabectedin: A Case Report

Background Myxoid liposarcoma is sensitive to trabectedin, but less sensitive to eribulin. Case presentation A 47-year-old man presented to our hospital with a right leg mass, biopsy of which revealed myxoid liposarcoma. Surgical resection was performed and perioperative chemotherapy was administered. Eighteen years postoperatively, the patient developed pericardial metastasis causing cardiac tamponade, and radiotherapy was administered. One year later, mesenteric metastasis occurred and the tumor was resected. One year later to this, multiple metastases, including recurrent mesenteric metastases, occurred. As the metastases progressed after two cycles of trabectedin treatment, eribulin was initiated, resulting in a partial response. Eribulin was continued for 18 months without severe adverse events. Genetic testing of the resected mesenteric tumor revealed a PIK3CA (p.H1047R) mutation, and immunohistochemistry for phosphorylated AKT was negative. Conclusions This report of long-term successful treatment of trabectedin-resistant myxoid liposarcoma with eribulin suggests sensitivity mechanism to eribulin in myxoid liposarcoma with PIK3CA mutation.