Urothelial Carcinoma of the Native Ureter in a Kidney Transplant Recipient

Abstract

A 56-year-old woman who underwent cadaveric kidney transplantation 44 months earlier had hydronephrosis of the left native kidney diagnosed on routine sonography. She also had chronic urinary tract infection but not gross microscopic hematuria. History included diabetes mellitus, gout, hypertension and hyperlipidemia. Left retrograde pyelography (RP) showed complete obstruction of the left native proximal ureter (part A of figure, arrow). Multidetector computerized tomography urography (MDCTU) revealed a fork sign at the left proximal ureter (part B of figure, arrow) and a spindle sign at the left middle ureter (part B of figure, arrowheads), suggesting urothelial carcinoma (UC). Although urine cytology was negative for malignancy, left ureteroscopy revealed a proximal ureteral mass subsequently proved on biopsy to be UC. The patient underwent bilateral nephroureterectomy with bladder cuff excision. Histological examination confirmed UC in the left native proximal and middle ureter with periureteral fat invasion. The patient died of brain and bone metastases 8 months after surgery, although there was no clinical or radiological evidence of metastasis at surgery. In Taiwan kidney transplant recipients have a reported 4.1% incidence of UC involving greater than 90% of the native upper urinary tract. 1 The most common presentation is gross hematuria followed by chronic urinary tract infection or microscopic hematuria. Mean SD time from transplantation to UC diagnosis is 48.2 49.6 months. UC is usually diagnosed at cystoscopy or on RP. Approximately 50% of patients have hydronephrosis on sonography, of whom 23% have positive urine cytology. MDCTU accurately diagnosed UC in patients with gross hematuria and detected more UC of the native upper urinary tract in kidney transplant recipients than RP. 2 Nonetheless, a careful search for imaging signs suggestive of UC throughout the entire native upper urinary tract is necessary and important on MDCTU to achieve a correct diagnosis because these native upper tracts are small and poorly functioning.