Robot‐Assisted Laparoscopic Partial Nephrectomy for Mixed Epithelial and Stromal Tumor of Kidney: A Case Report

Mixed epithelial and stromal tumor (MEST) of the kidney is a rare and distinctive neoplasm accounting for 0.2% of all renal tumors. The general treatment for MEST typically involves radical nephrectomy or partial nephrectomy. We report a rare case of MEST successfully treated with robot-assisted partial nephrectomy (RAPN), which, to our knowledge, represents the first documented instance of this approach. The patient is a 53-year-old woman with an incidental right renal tumor. The patient visited a primary care physician for chest pain. Computed tomography (CT) scan revealed a 3.5-cm lesion in the upper pole of the right kidney and was suspected of renal cell carcinoma. The patient was subsequently referred to the department and was admitted to our department for RAPN. We experienced the first case of RAPN performed for MEST of the kidney. Histopathological and immunohistochemical analyses confirmed the diagnosis of MEST. This case highlights the feasibility of robot-assisted laparoscopic surgery as a minimally invasive treatment option for MEST.