Wilms Tumor (Nephroblastoma)

Pathophysiology of Wilms Tumor

1) Wims tumor is malignant renal tumor in children
2) occurs as both a sporadic tumor and as part of three genetic syndromes

Signs and Symptoms

1) most commonly presents as flank mass
2) abdominal pain
3) bowel and ureter obstruction
4) hematuria
5) hypertension
6) peritonitis from rupture and intraperitoneal hemorrhage of tumor

Characteristic Test Findings

Radiology – CT scan is diagnostic test of choice and shows a large renal mass

Histology/Gross Pathology

1) pale tan cut surface with foci of necrosis surrounded by a thin rim of renal cortex
2) nephroblasts
3) immature stroma and tubules
4) all syndromic Wilms’ tumors have nephrogenic rests

Associated Conditions

1) WAGR syndrome – Wilms’ tumor, aniridia, genitourinary defects, mental retardation
2) Denys-Drash syndrome – Wilms’ tumor, glomerulopathy, and sexual phenotype disorders
3) Beckwith-Wiedemann syndrome – Wilms’ tumor, gigantism, enlarged viscera, and macroglossia

Biochemistry

1) WAGR syndrome – associated wtih deletion of tumor-suppression gene WT-1 on chromosome 11
2) sporadic Wilms’ tumor is more associated with deletion of gene WT-2 on chromosome 11

Inheritance/Epidemiology

1) Wilms tumor most commonly presents at age 1-3 years
2) earlier presentation has better prognosis
3) sporadic cases – 99% of cases; 10% are bilateral
4) familial cases – both autosomal dominant and recessive inheritance
5) occurs in 1/10,000 births

Treatment

1) Wilms tumor is treated with surgical resection with chemotherapy and radiation 2) cure rates are 75-90%

Tips for USMLE

if a 2 year old girl is noticed by her mother to have a palpable mass in her right flank and CT scan shows a mass in the top part of her right kidney, think Wilms tumor