Long-term follow-up of metastatic renal myoepithelial carcinoma: case report and literature review

Background: Primary renal myoepithelial carcinoma is an exceptionally rare malignancy with limited data on optimal treatment, particularly in metastatic settings. Case Description: In 2020, Shenoy reported a dramatic response in a case of metastatic myoepithelial carcinoma with Ewing sarcoma breakpoint region 1- POU class 5 homeobox 1 (EWSR1-POU5F1) fusion arising from the left kidney using the Ewing Sarcoma vincristine, doxorubicin, cyclophosphamide/ifosfamide, etoposide (VDC/IE) chemotherapy regimen. Ten months post-treatment, the patient showed ~90% reduced disease burden on imaging. Subsequent treatment included consolidation vincristine, cyclophosphamide/ifosfamide, etoposide (VC/IE) chemotherapy, surgical resection of the remnant tumor, and follow-up imaging. Conclusion: The patient has been disease-free for 44 months off treatment and 5 years post-treatment initiation. To our knowledge, this is the first report of long-term disease-free survival in metastatic primary renal myoepithelial carcinoma. We also review the literature on this rare disease.