Unlike adult nephroblastoma, which is often associated with hematuria, the first thing that comes to attention in children with nephroblastoma is the presence of a mass in the abdomen. Nephroblastoma can occur anywhere in the kidney, and the renal pelvis is often compressed and deformed. The clinical presentation of nephroblastoma is not complex, but rather consistent. It is usually unilateral, and bilateral tumors are less common. The tumor has a smooth, moderately hard, non-pressure surface in the epigastric quarter and may extend beyond the midline pushing the abdominal viscera to one side. In a few cases, there may be anemia and abnormal urination. Occasionally, those with hematuria often have hypertension. 1, abdominal mass: 80% to 90% of cases are seen with abdominal masses, most of which are found unintentionally and may be asymptomatic, usually when the mother is bathing or dressing the child, or when medical personnel do a general examination for other reasons and find the presence of a mass in the abdomen. The mass is located in one side of the abdomen, oval in shape, with smooth and flat surface, solid texture, no pressure pain, clear inner and lower border of the edge, upper border is obscured by the edge of the ribs, and cannot be touched, and the waist can be felt to be filled by the tumor when palpating with both hands. The tumor is relatively fixed and cannot be moved. The size of the mass varies, and the larger ones can occupy 1/3 to 1/2 of the whole abdomen. In more advanced cases, the mass often exceeds the abdominal midline and pushes the abdominal viscera to the opposite side. It should be noted that repeated palpation and squeezing of the tumor can prompt the tumor cells to enter the blood stream and distant metastasis can occur, thus special attention should be paid. 2. Pain and digestive symptoms: It has been reported that the first symptom of 25% of nephroblastoma is back and leg pain. In fact, most of the pains are unnoticed because they are not serious and children are not good at describing them. Children may have acute abdominal symptoms in the event of a fall, fall or abdominal trauma. Occasionally, children may have sudden onset of pain due to sudden hemorrhage within the tumor, hyperinflation of the renal envelope or temporary obstruction of the ureter by a blood clot. Children often have vague gastrointestinal symptoms, such as nausea, vomiting and loss of appetite. Hematuria: Hematuria occurs in 20% of cases, and in about 10% of cases hematuria is noticed as the first symptom and the diagnosis of tumor is made. It is usually painless and intermittent total hematuria with small amount, sometimes accompanied by blood clots. When a pediatrician sees this symptom, even if a mass is not palpable in the abdomen, an ultrasound, intravenous pyelogram, or CT should be done to potentially detect a small tumor in the central part of the kidney. In most cases, however, hematuria is a more advanced symptom and the tumor is already quite large, infiltrating the renal calyces and entering the renal pelvis. Microscopic examination of urine contains multiple red blood cells in about 1/3 of cases. 4. Fever: Children with nephroblastoma may have different degrees of fever, mostly intermittent, and high fever (39℃) is rare. It has been noted that children with vomiting almost always have increased body temperature due to dehydration and cases with metastases or necrosis in the tumor. Hypertension: There may be a number of children with mild or severe hypertension, but it is often reported infrequently because of the neglect of measuring blood pressure in infants and children. However, there are many cases of severe hypertension in the literature, but the hypertension decreases after the tumor is removed. This phenomenon suggests two possibilities: either the tumor compresses the renal artery and causes the blood pressure to rise, or the tumor itself produces some kind of pressure-raising substance. When localized or metastatic lesions recur, blood pressure rises again, and after the lesions disappear with radiotherapy and chemotherapy, blood pressure also decreases, which further indicates that the tumor may be secreting some kind of antihypertensive substance. In children with nephroblastoma, plasma levels of renin, or hypertensive proteinogenase, are higher than those of normal children, and return to normal after tumor removal. In recent years, renin has been quantified from the leachate of nephroblastoma, and its amount is much higher than that of normal kidney cortex. 6. General condition: Generally speaking, there is a certain impact on the general condition, such as loss of appetite, mild wasting, depression and not as lively as before, pallor and general discomfort. When there is metastasis in the lung, the general condition is more declined, but there are few symptoms such as cough and hemoptysis. 7. Symptoms of tumor rupture and metastasis: Occasionally tumor rupture occurs spontaneously or after injury, usually with severe pain first and acute anemia in the child, mostly diagnosed as liver or spleen rupture. The tumor may rupture in the abdominal cavity, or in the lumbar fossa of the retroperitoneal space, or the tumor may only be fissured with hematoma under the envelope. The tumor mainly metastasizes through blood stream, so metastasis to lung is the most common. After metastasis, there are few symptoms such as cough and hemoptysis, so X-ray lung examination is most important. Liver metastasis is less common.