Mixed epithelial and stromal tumor of the kidney extending to the proximal ureter in a 41-year-old female.

We report the case of a 41-year-old pregnant female who presented with a complicated urinary tract infection. Further imaging revealed left hydronephrosis and filling defects extending from the proximal ureter to the upper pole of the kidney, with the presumed diagnosis of a fibroepithelial polyp. The patient underwent a four-stage percutaneous and ureteroscopic ablation and resection. Following the procedure, pathology instead confirmed the presence of a Mixed Epithelial and Stromal Tumor of the Kidney. For lesions that extend intraluminally into the ureters, a ureteroscopic and percutaneous resection can be considered as an alternative surgical approach.