Failure of percutaneous endoscopic resection of a renal cystic nephroma on longer-term follow-up.

In 2005 we reported in this journal the treatment of cystic nephroma, a rare but presumed benign renal tumor, with percutaneous resection. Initial follow-up confirmed removal of the intra-pelvic portion of the cystic nephroma and persistence of the unresected intra-parenchymal portion. Surveillance with computed tomography revealed gradual regrowth of the mass, ultimately resulting in a size greater than that at the time of initial resection. Laparoscopic radical nephrectomy without adrenalectomy revealed benign cystic nephroma.