Abstract Ureteric involvement is described rarely in nephroblastoma, the most common pediatric renal tumor. This clinicopathological, descriptive retrospective study was conducted to elucidate the prevalence and histomorphological features of ureteric involvement by nephroblastoma. Of 454 nephroblastomas diagnosed in the 25-year study period, 32 displayed ureteric involvement; 21 and 11 demonstrated prolapse and invasion, respectively. The patient cohort had a mean age of 47.3 months and mainly advanced stage disease. Pre-operative radiological and intra-operative assessments identified ureteric involvement in 4 and 13 patients, respectively, but distinction between ureteric prolapse and invasion was not possible. Histopathological assessment of the primary renal tumor demonstrated exclusive triphasichistomorphology in all 32 nephroblastomas. Favorable histology, diffuse anaplasia and nephroblastomatosis were present in 28, 4 and 7 tumors, respectively. Re-appraisal of 17 post-treated tumors were classified by SIOP criteria as mixed(6), stromal(4), anaplastic(4) and regressive(3) types. The ureteric component displayed triphasic(11), biphasic(5) and monophasic(1)histomorphology. The staging profile of patients with ureteric prolapse was stages I(3), II(5), III(6), IV(6) and V(1). The staging profile of patients with ureteric invasion was stages I(0), II(2), III(3), IV(4) and V(2). Distant metastases were present in 10/32 patients. Follow-up of 32 patients confirmed 21 that were tumor-free, 7 with recurrent disease and 4 fatalities; of those that remained tumor-free, 11 had advanced disease. Even in advanced tumor stages, complete excision of the urinary tract tumor and optimal treatment of disseminated malignancy are pivotal to overall patient management and outcome.
Keywords: nephroblastoma; Wilms’ tumor; ureter; invasion; prolapse; kidney; renal