•Evidence is strong for a genetic/developmental etiology.
•The tumor may arise as a result of failure of blastemal tissue to differentiate into normal renal structures.
in children, usually under age 5.
•Peak incidence between ages 1 and 3.
•Occurs in approximately 7 in a million children per year in the
•Occurs as part of WARG syndrome (Wilms tumor, aniridia,
retardation, genital abnormalities).
•Occurs as part of Denys-Drash
syndrome (gonadal dysgenesis and nephropathy leading to renal
•Occurs as part of Beckwith-Wiedemann syndrome (organomegaly, hemihypertrophy, renal cysts, adrenal cytomegaly).
presentation is that of a large abdominal mass in a child, usually 1 to 5
•The neoplasm is aggressive and metastasizes widely, but is responsive to combination therapy.
|General Gross Description|
•At the time of detection, Wilms tumors are usually large and dwarfs the
•The cut surface is usually soft, fleshy and
•Irregular areas of hemorrhage and necrosis may be present.
|General Micro Description|
•The classic Wilms tumor is triphasic showing areas that are blastemal
(non-descript undifferentiated small round cells), areas that show
epithelial differentiation (tubules, glomeruloid structures) and areas that
show stromal differentiation (spindle shaped cells, skeletal
•Mitotic figures are usually plentiful.
• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 462-464.