The typical presentation of a child with a WT is an asymptomatic mass. Parents frequently bring Wilms' tumor to the attention of the doctor after they have noticed a slight swelling or a lump in their child's abdomen. Often they are convinced, that the mass was not there a few days ago. Other complaints, signs or symptoms are found in about 20 % or less including pain, microscopic or gross hematuria, fever, gain loss and few others like high blood pressure. In Germany in about 10 % of patients an early diagnosis of WT is done during regular childhood precautions in an asymptomatic child. Hypertension is caused by an increase in renin activity and is sometimes difficult to control. Few patients present with a coagulopathy caused by an acquired von Willebrand syndrome. In most cases an acquired coagulation disorder and the hypertension will resolve after tumornephrectomy. Sometimes an emergency situation with a rapid abdominal enlargement and anemia caused by an intratumoral bleeding needs immediate surgery. A thrombus of the V. Cava can grow up into the right ventricle and can lead to massive cardiac insufficiency or can cause pulmonary emboli.
About 12 % of patients with a WT have an underlying syndrome. One third of the syndromes affect the urogenital system, in 15 % a hemihypertrophy can be diagnosed, whereas all other syndromes or malformations are rare including aniridia and Denys-Drash syndrome in 4 -5 % and Beckwith-Wiedemann syndrome in 2-3 %.
13 % of patients will be diagnosed primarily with metastases. More than 60 % of these patients have metastases to the lung and more than 10 % to the liver. Extraregional lymphnode involvement occurs in less than 10 % of patients with metastatic disease. Metastases to bone and brain are uncommon. If metastatic disease occurs in infants with a renal tumor, a rhabdoid tumor of the kidney should be considered, for metastases are very unlikely in WTs in this age group.
