Diagnosing tumors of the urinary system

2021-07-01 01:19 PM

In children, the malignancy of the kidney is nephroblastoma (Wilm's tumor), which is the most common malignancy of the abdominal cavity in young children.


Cellularly, renal epithelial tumors are classified as non-renal epithelial tumors.

Malignant renal epithelial carcinoma accounts for 85% of all adult renal tumors. Benign renal epithelial tumors are very rare, including adenoma, oncocytoma, and neoplasm.

Non-epithelial neoplasms are benign fibro-muscle-fatty tumors (angiomyolipoma). Other rare types such as lipoma, hemangioma, lymphangioma, fibrosarcoma, lipoma, muscle sarcoma...

In children, the malignancy of the kidney is nephroblastoma (Wilm's tumor), which is the most common malignancy among abdominal tumors in children 1 to 8 years of age (>90%), accounting for 12% of all cases. malignancies of the kidney of any age. in general. Tumors are usually 3-25cm large, sometimes accounting for 1/3 of the baby's weight. The internal components of the tumor include hemorrhagic necrosis, cocoon, and fibrous tissue.

Renal tumors may be discovered incidentally on ultrasound or computed tomography and may present with clinical signs such as hematuria (50%), back pain, palpable mass, persistent fever, or other signs of renal involvement. metastatic renal tumor.

Computed tomography is a diagnostic technique, and ultrasound is a common means of detecting kidney masses. Evaluation of tumor extension requires computed tomography. Intravenous urography is only used to examine the invasive urinary tract, but only 1-2 films are needed immediately after contrast-enhanced computed tomography (post scanner). Magnetic resonance is reserved for patients with iodine allergy, consider hemorrhagic cysts, and assess venous invasion. In general, the majority of tumors are small < 3 cm (of which 20% are benign), imaging techniques are not clear, need to be computed tomography with contrast injection, especially magnetic resonance and surgery. art. Before a detected mass, the purpose of imaging is: Differentiate between true mass and pseudotumor; Distinguish between solid and fluid masses; If it is a solid mass, it is malignant or benign;

Renal parenchymal tumor - Renal cell carcinoma

Kidney cancer accounts for 3% of all cancers in adults, 95% over 50 years old, twice as many men as women. Predisposing factors are polycystic kidney, acquired polycystic kidney failure, horseshoe malformation kidney, smoking. Other types of renal malignancies such as metastases, lymphomas, sarcomas, nephroblastoma in adults.

Intravenous urogram, rarely indicated. As the test of choice for hematuria, this technique best examines the urinary tract. Intravenous urography only allows the diagnosis of kidney cancer when there are images of calyx amputation and invasion of the renal calyces. In addition, renal margin deformity and calcification are indicative of malignancy. The venous urography may be normal when the tumor is not large.

Ultrasound distinguishes between solid and fluid masses. If it is a solid, consider acoustic structure, which can be reduced, copper or hyperechoic, see negative homogeneity, calcification. If it is a mass, look for buds or cysts within the cyst. Ultrasound can show lymph node metastasis, venous invasion. In general, when ultrasound detects a solid mass, computed tomography is needed to better assess the nature, invasion, and metastasis.

CT differentiates solid or fluid mass, detects small calcifications, intratumorally hemorrhage, and tumor perfusion. In most cases, benign and malignant tumors can be distinguished. Consider dilated, invasive urinary tract

CT scan checks lymph node metastasis, invades a surrounding area, vascular invasion, distant metastasis, the basis for staging tumor progression, necessary for treatment.

Tumor of renal pelvis and ureter, bladder

It is a malignant urothelial tumor. Accounts for 6 - 10% of malignant kidney tumors. Major risk factors: urinary stones, infection, smoking, taking too much phenacetin. It is common over 50 years old, twice as often in men than in women. Benign tumors are polyps, which are common in the age group of 20-40 years.

Urinary tract malignancies are predominantly transitional cell carcinoma (85%), in addition to squamous cell carcinoma (15%). Cancer metastasis to the urinary tract is rare. Urinary tract tumors are common in order; in the bladder, renal pelvis, and ureters.

Venous urography

For infiltrates, the image is narrow, the border is irregular, often causing water retention. For warts, there is a bright defect in the urinary tract, the border may be irregular, which can cause water retention in the upper urinary tract. It should be differentiated from blood clots and non-contrast stones. Stones and blood clots are displaced, surrounded by a contrast border. Blood clots change shape over time. Tumors of the urinary tract (pyelonephritis, ureters, bladder), with legs attached to the wall, where there is no contrast border surrounding the tumor.


Difficult to diagnose pyelonephritis, ureter; if there is no hydronephrosis. Ultrasound detects stones easily. Bladder tumor on ultrasound showed echogenicity in bladder with negative voiding urine. Ultrasonography can show the extent of the bladder wall and extramural invasion.

Computer class cutting

The tumor is shown to have decreased density compared to the renal parenchyma, and an increase in density after contrast injection. Computed tomography can show blood clots, the density is higher than the tumor. Stones in the urinary tract have a much higher density than tumors (20 - 30 UH) and clots (50 - 70 UH). The density of stones ranges from 100 to over 1000 UH depending on the composition of the gravel.

Tumors of the renal pelvis can penetrate the parenchyma, change the renal margin, can narrow the excretory tract, dilate the renal calyces; can be detected on venous orographs. Computed tomography is easier to detect pyelonephritis that invades renal parenchyma, and at the same time distinguishes it from renal parenchymal tumor invading the renal pelvis.

Figure: the image of kidney block effect due to the tumor, a cyst.

Figure: Urinary tract defect due to non-contrast stone and tumor.