Ureteral extension in Wilms' tumor: a report from the National Wilms' Tumor Study Group (NWTSG).
BACKGROUND
Extension of Wilms' tumor into the ureter is a rare event. We reviewed the National Wilms' Tumor Study Group (NWTSG) database to define the clinical presentation, associated pathologic features, and clinical outcome of these patients.


METHODS
Records of children identified to have ureteral extension of Wilms' tumor enrolled in NWTS-3, 4, and 5 were reviewed. Presenting symptoms, diagnostic studies, histopathologic findings, operation performed, and outcome were recorded. The NWTS-5 surgical data were prospectively collected as part of the quality assurance program.


RESULTS
Forty-five children were identified with ureteral extension. For NWTS-5, the incidence of ureteral extension was 2%. Clinical presentations were gross hematuria in 22 patients, 2 had passage of tissue per urethra, and 1 child had a urethral mass. The remainder had nonspecific presentations. Ureteral extension was seen on preoperative imaging in 14 patients, intraoperatively in 22, and on pathologic examination in 9 patients. Hydronephrosis was noted in 12 patients, and there was nonfunction of the kidney in another 8. Laterality of the tumor was right side in 26 and left in 19. Cystoscopy was performed in 12 children. Findings included tumor seen at the ureteral orifice in 6 patients and bleeding from the orifice in one child. All patients had radical nephrectomy including partial ureterectomy. The ureteral margin was positive in 3 patients, including 2 of the 7 with separate removal of the ureteral extension. The number of patients in each clinical stage was as follows: stage I, 10; stage II, 18; stage III, 14; and stage IV, 3. The tumor extended into the proximal ureter in 23 patients, distal ureter in 13, 7 had extension into the bladder, and 1 had urethral involvement. The level of ureteral extension was not clearly noted in the 45th child. The median follow-up was 96 months. Overall, 41 of 45 patients were alive at last contact. There were 3 deaths because of tumor in patients with unfavorable histologic tumors, and 1 because of treatment toxicity in a child with favorable histologic findings.


CONCLUSIONS
Ureteral extension occurs in approximately 2% of patients with Wilms' tumor. The diagnosis should be suspected in patients with gross hematuria, hydronephrosis, or nonfunctioning kidney. Cystoscopy with retrograde ureterogram may aid in preoperative diagnosis in these patients. Preoperative diagnosis is important because complete resection of the involved portion of ureter at the time of nephrectomy can avoid residual disease and the need for second surgery or radiation therapy.
Ritchey
Michael
M
Department of Urology, Mayo Clinic Arizona, Scottsdale, AZ 85259, USA.
Daley
Shane
S
Shamberger
Robert C
RC
Ehrlich
Peter
P
Hamilton
Thomas
T
Haase
Gerald
G
Sawin
Robert
R
D002675:Child, Preschool; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D009361:Neoplasm Invasiveness; D011446:Prospective Studies; D016896:Treatment Outcome; D014516:Ureteral Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D009396:Wilms Tumor / Q000473:pathology*
Radiology. 1987 May;163(2):385-6
3031726
Br J Urol. 1974 Aug;46(4):409-13
4370540
Pediatr Pathol. 1990;10(1-2):1-36
2156243
Pediatr Radiol. 1997 Oct;27(10):818-20
9323251
Pediatr Nephrol. 2000 Jan;14(1):59-61
10654334
Proc Staff Meet Mayo Clin. 1947 Mar 5;22(5):94-8
20287353
Urology. 1980 Apr;15(4):370-3
6249008
J Pediatr Surg. 1988 Dec;23(12):1131-4
2853218
Ann Surg. 2001 Jul;234(1):116-21
11420491
J Urol. 1972 Jan;107(1):142-3
4333460
J Urol. 1957 Apr;77(4):593-6
13417297
Ann Surg. 1968 Jan;167(1):127-31
4294819
Pediatr Radiol. 1995 Nov;25 Suppl 1:S68-9
8577559
J Urol. 1980 Jul;124(1):130-1
6251282
J Urol. 1976 Apr;115(4):467-8
177791
J Clin Oncol. 1985 Apr;3(4):521-31
2984345
J Urol. 1995 Jun;153(6):1981-3
7752377