Renal adenocarcinoma is a renal cell carcinoma originating from the epithelium of the renal tubules. Manifestations are lower back pain, hematuria, kidney enlargement, anemia, cachexia. The tumor may metastasize to the lungs, paracaval and paraaortic lymph nodes, bones, liver, adrenal glands, and the opposite kidney. Pathology is diagnosed during ultrasound of the kidneys, cystoscopy, excretory urography, ureteropyelography, CT of the kidneys. Morphological verification of the diagnosis is carried out by puncture biopsy of the kidney and histological examination of the biopsy. Detection of renal adenocarcinoma is an indication for nephrectomy followed by radiation therapy.
C64 Malignant neoplasm of the kidney, except for the renal pelvis
Renal adenocarcinoma accounts for about 2.5% of the number of neoplasias of various localizations. In modern urology, adenocarcinoma is the most common histotype of kidney cancer in adults. Among all kidney tumors, adenocarcinoma accounts for 90% of cases. The disease usually develops at the age of 40-70 years; it affects the left and right kidney with the same frequency; it is diagnosed 2 times more often in men.
Causes of renal adenocarcinoma
Kidney adnocarcinoma has a polyethological and completely unclear nature. Kidney diseases (glomerulonephritis, pyelonephritis), trauma play a certain role in the development of the tumor; the effect of chemical agents (nitrosoamines, hydrocarbons, aromatic amines), radiation exposure, intoxication (smoking) on the renal tissue. Neoplasia often develops from a benign kidney adenoma, therefore, all identified kidney neoplasms are subject to removal and histological examination. The correlation of adenocarcinoma with obesity and hypertension was noted. Less often, the causes of tumor development are dysontogenetic disorders, hereditary forms of kidney cancer.
Macroscopically, kidney adenocarcinoma looks like a node of a soft-elastic consistency. The incision shows intermittent areas of hemorrhage and necrosis, giving the tumor a mottled appearance. Tumor growth can be multidirectional – towards the renal capsule or the cup-pelvic complex; adenocarcinoma sprouts renal veins, inferior vena cava, adjacent tissues quite quickly; metastasizes to lymph nodes, lungs, bones, liver, brain. The microscopic structure is represented by strands and clusters of polygonal cells having a light protoplasm containing glycogen and lipids; the tumor stroma is weakly expressed.
Classification of kidney adenocarcinoma
Adenocarcinoma of the kidney is a type of renal cell carcinoma (hypernephroid cancer) and may have a different degree of differentiation. The international classification according to the TNM system identifies the following stages of pathology:
- T1 – the spread of the tumor is limited to the renal capsule
- T2 – tumor germination of the fibrous capsule of the kidney
- T3 – the vascular pedicle of the kidney or paranephral fatty tissue is involved in the tumor process
- T4 – the tumor grows into the nearest organs;
- Nx – preoperative assessment of regional lymph nodes is not possible
- N1 – regional metastasis is determined using radiological or radioisotope methods
- M0 – absence of distant metastases
- M1 – a single metastasis in distant organs is determined
- M2 – multiple distant metastasis is determined.
Distant metastases are detected in 50% of patients, and the germination of a renal vein tumor is detected in 15%. More often, distant metastases are located in the lungs (54%), regional paracaval and paraaortic lymph nodes (46%), bone skeleton (32%), liver (36%), opposite kidney (20%), adrenal glands (16%). Metastases can manifest clinically even before the primary focus is detected or occur some time after nephrectomy for kidney cancer. In the clinical course of renal adenocarcinoma, there is a latent (latent) period, as well as periods of local and general manifestations.
Symptoms of renal adenocarcinoma
There are no clinical manifestations in the latent period. The development of local symptoms is accompanied by the appearance of macrohematuria and pain, an increase in the kidney. Hematuria is observed in 70-80% of patients with renal adenocarcinoma. The excretion of blood in the urine occurs unexpectedly, more often in the form of threadlike clots 6-7 cm long. Hematuria is usually episodic, ceasing and resuming again. In the case of intense renal bleeding (profuse hematuria), thrombosis of the renal veins, blockade (tamponade) of the bladder and acute urinary retention may occur.
Pain syndrome occurs in 60-70% of cases. The pain is dull, aching, localized in the lower back, radiates to the groin and hip; at the height of hematuria, it can increase to renal colic. Kidney enlargement is noted in 75% of cases. In the later stages, a tumor palpable through the abdominal wall is determined. With the germination of adenocarcinoma of venous vessels, women have varicose veins of the labia, men have varicocele.
In the period of general manifestations, weight loss, weakness, hypertension progresses; there is a causeless persistent increase in body temperature, anemia, cachexia. In advanced stages, paraneoplastic amyloidosis and nephrotic syndrome develop (generalized edema, massive proteinuria, hypoproteinemia, hypoalbuminemia, etc.).
Laboratory and instrumental techniques are used in the diagnosis of renal adenocarcinoma. In the general analysis of urine, pronounced hematuria, moderate proteinuria is detected; in the blood – normochromic anemia, an increase in ESR. Ultrasound, endoscopic and X-ray diagnostics play a leading role in the detection of renal adenocarcinoma. An informative method for confirming adenocarcinoma is ultrasound of the kidneys, which, in addition to imaging the tumor, allows for a targeted puncture biopsy of the kidney with the collection of tumor tissue for morphological examination of the biopsy.
Cystoscopy is resorted to at the time of hematuria, which allows you to determine the ureter from which blood is released. Excretory urography makes it possible to consider uneven contours and enlarged kidney sizes, to identify deformation, amputation of cups, deviation of the ureters, defects in filling the pelvis. In some cases, retrograde ureteropyelography, renal angiography, and nephroscintigraphy are indicated.
The fact of distant metastasis of adenocarcinoma is established by X-ray of the lungs, skeletal scintigraphy, ultrasound of the liver, adrenal glands and retroperitoneal space. The neoplasm is differentiated from kidney stones, kidney adenoma, chronic glomerulonephritis, pyonephrosis, kidney tuberculosis, polycystic.
Treatment of renal adenocarcinoma
In this pathology, it is optimal to carry out combined treatment, including radical kidney surgery and radiation therapy. Partial nephrectomy may be performed in the early stages. With a common process, a total nephrectomy is performed, with the removal of paranephral and retroperitoneal tissue with regional lymph nodes. The germination of the tumor of the inferior vena cava and even the presence of single distant metastases do not prevent the performance of nephrectomy. With single metastases to the lungs, the second stage is the removal of the metastatic focus. The combination of surgical treatment with radiation increases survival in renal adenocarcinoma.
A total cancerous lesion of both kidneys may require a binephrectomy with the transfer of the patient to hemodialysis. A common form of renal adenocarcinoma, characterized by extensive metastasis and tumor germination, involves symptomatic and palliative treatment with radiation and chemotherapy.
Prognosis and prevention
After nephrectomy, patients are subject to the supervision of a urologist, dynamic lung radiography for the purpose of early detection of metastases. The long-term prognosis is unfavorable: there is a high percentage of late metastasis of the tumor to the bones and lungs. After total nephrectomy, 40-70% of patients overcome the 5-year survival threshold. To exclude the possibility of developing kidney adenocarcinoma, it is recommended to follow a healthy lifestyle, exclude bad habits, and timely treatment of kidney diseases. It is necessary to carry out preventive ultrasound of the kidneys and immediately consult a nephrologist (urologist) in case of pain in the lower back or blood in the urine.