Wilms tumor

Introduction to nephroblastoma Wilmstumor is the most common abdominal malignant tumor, and its incidence is the first in children's abdominal tumors. Tumors mainly occur in the first 5 years after birth, especially in 2 to 4 years old. The number of cases on the left and right sides is similar, and 3 to 10% are bilateral, or occur simultaneously or sequentially. There is no difference between men and women, but most of the reports are male. Slightly more than women, individual cases occur in adults. It is formed by the development of the posterior kidney from embryogenesis, and the tumor consists of components that are very similar to the kidney cells. basic knowledge The proportion of illness: 0.004%-0.007% Susceptible people: no special people Mode of infection: non-infectious Complications: nephrotic syndrome, acute renal failure, varicocele

Cause of nephroblastoma

(1) Causes of the disease

In the occurrence of this disease, it may be related to dysplasia and many chemical and biological factors. The nephroblastoma may be the result of abnormal proliferation of the posterior kidney embryo without differentiation into the renal tubule and glomerulus, Bove and McAdams ( 1976) suggests that the nephroblastomosis complex may be converted to nephroblastoma. Knudson and Strong (1972) suggest that Wilms tumors can be classified into two types, genetic and non-genetic, depending on whether the germ cells are mutated. If it is in hereditary form, the tumor occurs earlier and is more likely to occur in both bilateral and multi-centered forms. All bilateral nephroblastoma and 15% to 20% of unilateral lesions are genetically related. In addition, hereditary doubles The incidence of tumors in the offspring of lateral nephroblastoma can reach 30%, while that in unilateral lesions is about 5%. Hoffinan (1989) and Koufos (1984) found the absence of recessive tumor suppressor genes on 11p13 (WT1). In patients with Beckwith-Wiedemann syndrome, 11p13 ends are found to have allelic heterozygosity with 11p15 (WT2). Interestingly, WT1 plays an important role in normal kidney embryogenesis, and the absence of this gene will lead to urinary tract. Genital dysplasia (Kreidberg, 1993), about 15% of children with nephroblastoma have other congenital malformations, and the American Wilms Tumor Study Group (NWTS) study shows that 1.1% of children with nephroblastoma have an iris deficiency , much higher than the normal population (0.2%), often combined with genitourinary malformations (cryptorchidism, hypospadias and renal fusion or ectopic), external ear malformations, mental retardation, head and face deformities, groin or umbilical hernia (Haicken and Miller, 1971), 2.9% had unilateral limb hypertrophy (Janik and Seeler, 1976), often with embryonic carcinoma, adrenocortical carcinoma, hepatoblastoma, and, in addition, children with nephroblastoma can be combined with other Site of malignant tumors (sarcoma, adenocarcinoma and leukemia).

Embryologically, the persistent post-renal embryonic group fails to differentiate into glomeruli and renal tubules and undergoes abnormal proliferation, which develops into nephroblastoma, which can occur in hereditary or non-genetic forms. Inherited form, the tumor occurs earlier, more easily in both bilateral and multi-centered forms, all bilateral nephroblastoma and 15% to 20% of unilateral lesions are related to heredity, but in the etiology of Beasc0 et al, Genetic factors are not important, and only 1% to 2% of patients have a family history.

(two) pathogenesis

The pathogenesis of this disease is unknown, and may be related to abnormal development of the kidney embryo. This tumor is a malignant solid tumor composed of interstitial, germ and epithelium, including epithelial tissue, connective tissue, muscle tissue, bone tissue and nerve tissue. There is a capsule, the cut surface is grayish yellow, there may be cystic changes and necrotic hemorrhage area, adjacent renal tissue is compressed and atrophied, renal pelvis and renal pelvis can be deformed, blood transfer can occur in the early stage, common metastatic sites are lung, liver, brain, etc., 10 %45% of cases have renal venous and inferior vena cava with tumor thrombus, and lymphatic metastasis plays a secondary role. The prognosis of nephroblastoma is related to the structure of the tumor. The prognosis of typical nephroblastoma and partially differentiated cystic nephroblastoma is good. NWTS is divided into 5 stages, stage I: tumor is limited to the kidney, can be completely resected; stage II: tumor infiltration of perirenal fat or renal vein with tumor thrombus, but no obvious tumor after surgery Remaining; stage III: the tumor can not be completely removed, there is still residual after surgery, but limited to the abdomen, no blood transfer; stage IV: blood transfer to the lungs, liver, bone, brain, etc.; V: bilateral nephroblastoma.

Wilms tumor prevention

No special precautions, early detection and early treatment.

Nephroblastoma complications Complications nephrotic syndrome acute renal failure varicocele

The main complication of nephroblastoma is rapid tumor growth, and can directly spread or metastasize to the lung, liver, retroperitoneum, mediastinum, pleura, adrenal gland, bone, etc., causing multiple organ tumors, erythrocytosis is rare, the cause may be related to tumor Related to the production of erythropoietin (Shalet, 1967), if combined with nephrotic syndrome, form Wilms nephritis, sometimes combined with varicocele, hernia, testicular swelling, congenital heart failure, hypoglycemia, cortisol, acute renal function Failure, occasionally abdominal pain and low fever, but not serious, loss of appetite, weight loss, nausea and vomiting is a signal of advanced disease, tumor can also produce erythrocyte growth factor to cause polycythemia, a very small number of nephroblastoma spontaneously collapse, Clinically similar to acute abdomen.

Wilms tumor symptoms common symptoms liver metastasis irritability low fever high blood pressure abdominal mass cyst nausea fatigue dyspnea

Clinical manifestations of abdominal mass are the most common symptoms. About 75% of patients are treated with abdominal mass or bloating. Because the mass does not affect the nutrition and health of the child at a small time, there are no other symptoms, so the parents are giving When children bathe or dress, they are accidentally participated in the discovery, and the regular ministry is not subject to the attention of parents and delays the noble treatment. The mass is located on the side of the rib of the upper abdomen, the surface is smooth, medium hardness, no tenderness, and can be slightly active in the early stage. After the increase, a small number of cases can exceed the midline. At this time, although there is no long-distance transfer, the child is under the pressure of huge tumors, but may have shortness of breath, loss of appetite, weight loss, irritability, gross hematuria is rare, but microscopic hematuria can be as high as 25 %, high blood pressure can be seen in 25% to 63% of patients, generally after tumor resection, blood pressure returned to normal, experience, in addition, occasionally abdominal pain and low fever, but not serious, loss of appetite, weight loss, nausea and vomiting are many times In the late stage of the disease, the tumor can also produce erythrocyte growth factor to cause polycythemia, a very small number of nephroblastoma spontaneously rupture, doctors with acute abdomen Now similar.

Abdominal mass

Many Wilms tumors in early childhood are asymptomatic, and the weak abdominal mass of infants and young children is a characteristic of this disease. It is often found by parents or doctors accidentally touching the mass. The mass grows rapidly, the size of Wilms tumors varies greatly, and the diameter of small tumors can only be A few centimeters, a large tumor can be very large, so that it fills the abdominal cavity and affects breathing, causing difficulty in breathing; the tumor is easy to reach, solid, smooth, poorly active, and occasionally may have nodular sensation, solid and inactive can be associated with hydronephrosis or kidney Cyst identification, other physical findings including iris deficiency, partial body swelling, etc., often have high blood pressure and fever, blood renin activity and erythropoietin can also be higher than normal.

2. Hematuria

Because the tumor rarely invades the renal pelvis, the hematuria is not obvious. About 50% of the sick children start with abdominal pain, hematuria and fever account for 20% to 25%, systemic symptoms such as fatigue, discomfort, and weight loss are mostly late performance, 1/3 The initial age of the child is under 2 years old and 2/3 is under 4 years old.

3. Hypertension

Hypertensive patients are secondary to tumors with renin increase or tumor compression of the renal artery, the incidence of hypertension is 30% to 65%, late 10% to 25% of hematuria, poor prognosis, blood pressure can be restored after surgical removal of tumor normal.

4. Low back pain or abdominal pain

About 30% of cases have low back pain or abdominal pain, which may be caused by tumor hemorrhage. In addition, renal embryonal tumors may be characterized by polycythemia or Cushing's syndrome. Most of the disease is unilateral, 10% to 15% is double. Lateral, extrarenal renal embryonal tumors are rare, and only 10 cases were reported worldwide before 1990.

5. Congenital iris deficiency

The incidence rate is about 1.4%, also known as aniridia-neuroblastoma syndrome.

6. Other

Digestive tract can have nausea, vomiting, abdominal distension and other obstructive symptoms; or lower extremity edema, ascites and varicocele, caused by tumor compression of the inferior vena cava.

Staging of Wilms' tumor: It is a staged system combining clinical and pathological, about 1/2 belongs to stage I, 25% is stage II, 20% is stage III, the rest is stage IV, and the contralateral kidney appears simultaneously or sequentially. It is 5% to 10%.

Stage I: The tumor is confined to one kidney and can be completely removed.

Stage II: The tumor spreads to the outside of the kidney, but it can still be completely removed.

Stage III: The tumor cannot be completely removed, with residual lesions in the abdominal cavity.

Stage IV: blood transfer.

Stage V: bilateral Wilms tumor involving both kidneys (simultaneously or not).

Examination of nephroblastoma

1. Blood routine: generally mild anemia, hemoglobin is lower than normal, but there are also a few erythrocytosis, which may be related to the increase of erythropoietin.

2. Blood examination: normal renal function, decreased plasma protein, erythrocyte sedimentation rate generally increased by 15 ~ 90mm / h, extraordinarily advanced tumor deposition rate increased more significantly, considered to be an indicator of poor prognosis.

3. Chromosome examination: in the absence of iris-neuroblastoma syndrome, the 11th pair of short arm regions of the chromosome are missing.

4. Urine microscopy: Many have hematuria and proteinuria, but most of the urine can not find cancer cells.

5. It is not easy to distinguish from neuroblastoma.

6. Urinary X-ray film: The shape of the kidney disappears, and the soft tissue shadows with clear edges are visible. A few cases are scattered in fine calcification.

7. Urinary angiography: including renal motility, venography, renal angiography showed that the renal blood vessels were moved or straightened, tumor blood vessels appeared, early development of renal vein, uneven distribution of contrast agent, thickening of renal vein and obstruction of tumor thrombus This examination found that 2/3 of the children with pelvis and renal pelvis were squeezed, stretched, deformed or destroyed; 1/3 of the children were compressed due to the affected kidney, the renal pelvis was filled with tumor or renal blood vessel was not embolized. Development, or only a small amount of contrast agent into the renal pelvis, when the tumor is larger, the affected side of the ureter shifts to the midline.

8. B-ultrasound: B-ultrasound is very sensitive in identifying cystic or solid masses, which can provide diagnostic clues for cystic and solid mixed nephroblastoma.

9. CT scan: In addition to showing a large renal mass, due to hemorrhage, necrosis, cystic changes in the tumor, the mass is often heterogeneous, and even a lesion with a large cystic mass is formed, and the wall of the capsule is thick. Irregular, 15% of cases may have calcification, CT scan is the most effective aspect of identifiable entity or cystic, and other organs can be found, exclude the involvement of the contralateral kidney, and differential diagnosis of hydronephrosis, renal cystic disease, Adrenal tumors and hematoma, the most common metastatic site of Wilms tumor is the lung, chest X-ray and lung CT scan can be used to exclude metastases, other tests can be based on clinical needs, such as bone scan and liver scan or bone marrow examination.

10. Puncture biopsy: The tumor is caused by embryonic kidney tissue. It is a malignant mixed tumor composed of epithelium and interstitial. The tumor tissue includes gland, nerve, muscle, cartilage, fat, etc. The cut surface is grayish yellow and can be cystic. Change, flaky hemorrhage and calcification, no obvious boundary with normal kidney tissue, tumor destroys normal kidney tissue, deforms renal pelvis and renal pelvis, rarely invades renal pelvis, metastasis pathway is similar to renal cancer, bilateral nephroblastoma accounts for 5%~10 %, histopathological examination showed that the tumors were of different sizes, with a thin and brittle pseudo-envelope. The cut surface was fish-like, light yellow or gray, with necrosis, hemorrhage, and scattered pseudo-cysts with clear or bloody liquid.

In the case of a suspected tumor mass in the lumbar region of the child, a needle biopsy should be avoided to prevent the tumor from spreading, and surgical exploration is still necessary.

Diagnostic identification of nephroblastoma

diagnosis

Clinically, infants or children under the age of 10 should be considered for the possibility of nephroblastoma in the case of a progressive enlargement of the abdomen, especially if accompanied by abdominal pain, high blood pressure, or hematuria.

The disease mainly has the following clinical manifestations:

1. Abdominal mass: early asymptomatic, abdominal mass is often the first symptom, accounting for more than 90%, more often found in the bath for children, the typical symptoms are: weak infants have a large mass in the abdomen "Rohan belly", The mass of the mass is hard, the surface may have nodules, no obvious tenderness, and the late mass is fixed.

2. Low back pain or abdominal pain: About 1/3 of cases have waist or abdominal pain, which may be local discomfort or even colic, may be caused by intratumoral bleeding, such as acute pain accompanied by fever, abdominal mass, anemia, high blood pressure, often For tumor subcapsular hemorrhage, intra-abdominal rupture of the tumor can be manifested as acute abdomen.

3. Hematuria: Uncommon, can appear in the late stage of the disease, generally can not be found by the naked eye, but 75% of cases can have microscopic hematuria.

4. Weight loss and anemia face and irregular fever.

5. Hypertension: found in adult patients and some children, mainly due to renal tissue compression, excessive secretion of renin.

6. Congenital iris deficiency: The incidence rate is about 1.4%, also known as iris-free nephroblastoma syndrome.

7. Others: The digestive tract may have nausea, vomiting, abdominal distension and other obstructive symptoms; or lower extremity edema, ascites and varicocele, caused by tumor compression of the inferior vena cava.

Combined with urinary tract plain film, the soft tissue shadow of the affected side of the kidney can be seen. The angiographic findings are similar to those of renal cancer. Ultrasound and CT, MRI excretory urography can increase the shape of the kidney, the renal pelvis and renal pelvis deform, the tumor is large, and the residual kidney. When the tissue is small, the diseased kidney may not be developed, and there is little calcification in the local area, and the diagnosis of the disease may be considered.

In addition, once a clear diagnosis is made, the extent of local and distant involvement should be further clarified, and the stage of Wilms' tumor should be determined in order to determine the treatment plan.

Laboratory tests must be done blood, urine routine, blood urea nitrogen and creatinine, liver enzyme determination, such as suspected neuroblastoma, should check urine catecholamine metabolites and bone marrow puncture smear, such as children with high blood pressure, renin levels May rise, there are also reports of erythrocytosis, such as nephroblastoma complicated by congenital malformations, you should check the chromosomes.

Imaging practice examination is an important clinical diagnostic method. Intravenous urography is still an important and effective means. The affected side of the kidney is not developed or the surface work is now a kidney mass, that is, the affected side of the renal pelvis is squeezed, displaced, elongated or Destruction, 10% of cases due to tumor invasion of the kidney practice tissue too much or invade the renal vein without development.

If the child is treated with an abdominal mass, ultrasound examination should be performed first to distinguish the cystic mass, and the inferior vena cava can be detected. If the inferior vena cava tumor is suspected, the inferior vena cava should be performed as follows. For vena cava obstruction, superior vena cava and right heart catheterization should be performed. ct can determine the extent of primary tumor invasion, the relationship with surrounding skill tissues and organs, whether there are bilateral lesions, whether there is liver metastasis and the nature of the mass. The mass contains different ingredients, which may indicate whether it is a hamartoma. Some authors have proposed medical treatment. If the affected side is not developed or under the microscope, gross hematuria should be done with cystoscopy and retrograde pyelography, as the tumor is reported to be ipsilateral. Ureter, bladder and urethra, mri compared with ct, the former does not use contrast agent, but the price is more expensive, it is easier to distinguish the renal vein and vena cava, and must accumulate more cooperation experience.

Differential diagnosis

Differential diagnosis includes hydronephrosis, renal cystic disease, adrenal tumor, hematoma and neuroblastoma.

1. Hydronephrosis: Abdominal mass and abdominal distension, but the mass is sac sexy, with the upper and lower activities of the breath, no obvious anemia and weight loss, intravenous urography shows dilated renal pelvis or kidney, B-mode ultrasound shows large liquid Dark areas, each liquid dark area communicates with each other, the renal cortex becomes thin, CT examination has water density density and enlarged renal pelvis and renal cortex thinning, can be diagnosed as hydronephrosis, MRI examination can be from transverse image On the coronal or sagittal image, the renal pelvis, ureteral dilatation, water accumulation, radionuclide renal function dynamic imaging can also be displayed, mainly used to reflect renal function, and hydronephrosis is shown as renal pelvis and renal pelvis position and morphology. Radioactive defect area.

2. Polycystic kidney disease: manifested as bilateral abdominal mass, the age of onset is relatively late, there are renal dysfunction such as proteinuria, and the cystic mass can be touched in both kidneys. With the respiratory activity, the urinary X-ray film is generally free of calcification. Urinary tract pyelonephritis renal pelvis has multiple curved impressions, or stretched due to compression, elongated, B-mode ultrasound, CT examination showed double kidney shadow enlargement, renal cortex is occupied by multiple size cysts, each The liquid in the cyst does not communicate with each other.

3. Retroperitoneal neuroblastoma: occurs in infants and young children, showing abdominal mass, but the course of disease develops rapidly, urography, B-mode ultrasound, CT examination shows that the kidney is compressed and displaced, but the renal pelvis and renal pelvis are not change.

4. Retroperitoneal teratoma: Abdominal mass is similar, but the tumor grows slowly, the whole body condition is good, and the urinary tract X-ray plain film often has irregular calcified plaque. The imaging examination shows that the kidney is under pressure and the renal pelvis is normal.

The differential diagnosis of abdominal mass in children should include hydronephrosis, polycystic kidney (multicystickidney), neuroblastoma, teratoma and nephroblastoma.

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