Tumors of Kidney

Kidney tumors, also known as renal tumors, are tumors, or growths, on or in the kidney. These growths can be benign or malignant (cancerous). They may be discovered on medical imaging incidentally (i.e. anincidentaloma ), or may be present in patients as an abdominal mass, hematuria, abdominal pain, or manifest first in aparaneoplastic syndrome that seems unrelated to the kidney. The most common form of kidney cancer in adults is renal cell carcinoma. Renal cell carcinoma usually does not cause obvious symptoms, especially in the early stages. As a result, the cancer may not be discovered until it is advanced. Kidney cancer is a disease in which kidney cells become malignant (cancerous) and grows out of control, forming a tumor. Almost all kidney cancers first appear in the lining of tiny tubes (tubules) in the kidney. This type of kidney cancer is called renal cell carcinoma. Both benign and malignant tumours occur in the kidney, the latter being more common. These may arise from renal tubules (adenoma, adenocarcinoma), embryonic tissue (mesoblastic nephroma, Wilms’ tumour), mesenchymal tissue (angiomyolipoma, medullary interstitial tumour) and from the epithelium of the renal pelvis (urothelial carcinoma). Benign renal neoplasms constitute a rather large and heterogeneous group of renal lesions that can be found in the kidney. The Bosniak classification for renal cystic lesions is the most useful and widely employed method for characterizing renal cystic


INTRODUCTION
Kidney tumors, also known as renal tumors, are tumors, or growths, on or in the kidney. These growths can be benign or malignant (cancerous). They may be discovered on medical imaging incidentally (i.e. anincidentaloma ), or may be present in patients as an abdominal mass, hematuria, abdominal pain, or manifest first in aparaneoplastic syndrome that seems unrelated to the kidney.
The most common form of kidney cancer in adults is renal cell carcinoma. Renal cell carcinoma usually does not cause obvious symptoms, especially in the early stages. As a result, the cancer may not be discovered until it is advanced.
Kidney cancer is a disease in which kidney cells become malignant (cancerous) and grows out of control, forming a tumor. Almost all kidney cancers first appear in the lining of tiny tubes (tubules) in the kidney. This type of kidney cancer is called renal cell carcinoma.
Both benign and malignant tumours occur in the kidney, the latter being more common. These may arise from renal tubules (adenoma, adenocarcinoma), embryonic tissue (mesoblastic nephroma, Wilms' tumour), mesenchymal tissue (angiomyolipoma, medullary interstitial tumour) and from the epithelium of the renal pelvis (urothelial carcinoma). Besides these tumours, the kidney may be the site of the secondary tumours.

B. Urothelial cancer of kidney 1. Childhood renal cancer -wilms' tumor 2. Metastatic tumor, e.g. Ovarian carcinoma, bone cancer 2. BENIGN TUMOR
Benign renal neoplasms constitute a rather large and heterogeneous group of renal lesions that can be found in the kidney. These include the simple renal cyst, selected complex renal cysts, cortical and metanephric adenomas, angiomyolipoma, oncocytoma, the rarer cystic nephroma, mixed epithelial-stromal tumor, and leiomyoma.
Renal cysts remain the most common benign renal lesions, representing more than 70% of asymptomatic renal masses. The overwhelming majority of simple or minimally complex cysts require no further follow-up or therapy once diagnosed. The Bosniak classification for renal cystic lesions is the most useful and widely employed method for characterizing renal cystic lesions and assessing the likelihood of the presence of a concomitant malignancy within the cyst.

ONCOCYTOMA
Renal oncocytoma is the most common benign tumor that appears as an enhancing renal mass on cross-sectional imaging and is presumed to be RCC until surgical excision, representing one of the ultimate challenges in preoperative diagnosis for the urologist. It accounts for 3% to 7% of kidney tumors. Renal oncocytoma is a common benign renal tumor that is clinically and radiographically indistinguishable from RCC.
There may be a higher incidence of oncocytoma in older patients with a small renal mass as opposed to younger patients. Oncocytomas are derived from the distal renal tubules, similar to chromophobe RCC, and may represent a spectrum of neoplasia as evidenced in the Birt-Hogg-Dubé genetic syndrome. However, there is no evidence that oncocytomas undergo malignant transformation in sporadic cases. If oncocytoma is suspected preoperatively, a percutaneous core biopsy in addition to fine-needle aspiration may reliably provide a diagnosis when core tissue is available for additional immunohistochemical studies. Recent advancements in immunohistochemical markers have greatly improved the diagnostic accuracy of pathologic diagnosis from pathologic specimens and even core biopsy specimens. Frozen section analysis at the time of surgery may not reliably distinguish oncocytoma from RCC and should not be used to guide surgical strategy.

CYSTIC NEPHROMA
Cystic nephroma is a characteristic renal lesion with a bimodal age distribution and a benign clinical course. Diagnostic peaks occur primarily in the first 2 to 3 years of life, predominantly in boys, and again in the fourth and fifth decades with a significant (8 : 1) female prevalence. As with other renal lesions, presenting signs can include abdominal mass, pain, and hematuria, but the majority of cystic nephromas are incidental findings.
Several familial cases have been reported in the literature, and there have been anecdotal reports of sarcoma and clear cell carcinoma arising from cystic nephroma. most cystic nephromas are solitary, centrally located, and widely variable in size (mean size 9 cm) and commonly demonstrate curvilinear calcifications, herniation into the renal collecting system, and septal enhancement Consequently, reliable radiologic differentiation between cystic nephroma and cystic RCC in adults or Wilms tumor in children is not possible.

LEIOMYOMA
Leiomyomas are rare, benign tumors that may arise from smooth muscle cells anywhere along the genitourinary tract. In the kidney these tumors most commonly arise from the renal capsule, but renal pelvis and renal vein sites of origin have been reported Leiomyomas are found at autopsy with a frequency of 4.2% to 5.2%, but only a minority are discovered clinically, representing approximately 1.5% of all benign renal tumors treated surgically.
The characteristic appearance is of a small solid renal mass arising from the renal capsule. Nephron-sparing approaches are preferred when technically possible.

OTHER BENIGN RENAL TUMORS
A multitude of rare benign tumors derived from the various mesenchymal components of the kidney have been described and include multiple histiotypes, such as hemangioma, lymphangioma, juxtaglomerular cell tumor, renomedullary interstitial cell tumor, intrarenal schwannoma, and solitary fibrous tumor. Numerous rare benign tumors derived from the various mesenchymal components of the kidney have been described.
Radiologic differentiation from renal malignancy is not possible. Reninoma, a benign tumor of the renal juxtaglomerular cell apparatus, is an important but rare cause of secondary hypertension and hypokalemia.

MALIGNANT TUMORS Renal cell carcinoma in adult (RCC) Risk factors of RCC:
Smoking .
Sex: Men are about twice as likely as women to get kidney cancer. Obesity, Extra weight may cause changes to hormones that increase your risk. Using certain pain medications for a long time. This includes over-the-counter drugs in addition to prescription drugs. Having advanced kidney disease or being on longterm dialysis, a treatment for people with kidneys that have stopped working Having certain genetic conditions, such as von Hippel-Lindau (VHL) disease or inherited papillary renal cell carcinoma Having a family history of kidney cancer. The risk is especially high in siblings. Exposed to certain chemicals, such as asbestos, cadmium, benzene, organic solvents, or certain herbicides.
Having high blood pressure or medication used to treat it is the source of the increased risk. Black, The risk in blacks is slightly higher than in whites. Lymphoma. For an unknown reason, there is an increased risk of kidney cancer in patients with lymphoma.

Symptoms
In many cases, people may have no early symptoms of kidney cancer. As the tumor grows larger, symptoms may appear. Patient may have one or more of these kidney cancer symptoms: Blood in urine A lump in side or abdomen A loss of appetite Pain Weight loss that occurs for no known reason Fever that lasts for weeks and isn't caused by a cold or other infection Extreme fatigue Anemia Swelling in ankles or legs flank mass & Hematuria is classical triad of renal tumors, however it is also known as triad of death as it indicates advanced disease.
Kidney cancer that spreads to other parts of your body may cause other symptoms, such as: Shortness of breath Coughing up blood Bone pain

Investigation
To confirm a diagnosis of kidney cancer, we need a-

Stages of kidney tumor
These are the stages of kidney cancer. The higher the stage, the more advanced the cancer.

Stage III
A tumor that is in the kidney and in at least one nearby lymph node A tumor that is in the kidney's main blood vessel and may also be in nearby lymph node A tumor that is in the fatty tissue around the kidney and may also involve nearby lymph nodes A tumor that extends into major veins or perinephric tissues, but not into the ipsilateral adrenal gland and not beyond Gerota's fascia

Stage IV
Cancer has spread beyond the fatty layer of tissue around the kidney, and it may also be in nearby lymph nodes Cancer may have spread to other organs, such as the bowel, pancreas, or lungs Cancer has spread beyond Gerota's fascia (including contiguous extension into the ipsilateral adrenal gland). Tumor invades beyond Gerota fascia (including contiguous extension into the ipsilateral adrenal gland). N: REGIONAL LYMPH NODES NX Regional lymph nodes cannot be assessed N0 No regional lymph nodes metastasis N1 Metastasis in regional lymph node(s) Patient can survive with just a part of one kidney as long as it is still working. If the surgeon removes both kidneys or if both kidneys are not working, patient will need a dialysis or a new kidney (kidney transplant). Patient is not fit for major surgery for cancer then another option to help destroy the tumor is: A. Cryotherapy uses extreme cold to kill the tumor. B. Radiofrequency ablation uses high-energy radio waves to "cook" the tumor. C. Arterial embolization involves inserting material into an artery that leads to the kidney. This blocks blood flow to the tumor. This procedure may be done to help shrink the tumor before surgery.

M: DISTANT METASTASES
All these are experimental and result of these are inferior to surgery.

For Metastatic disease Biologic therapy for kidney cancer
This therapy uses immune system to fight cancer by boosting, directing, or restoring your body's natural defenses. Substances for biologic therapy are made body or in a lab. Examples of biologic therapy for metastatic kidney cancer include interferon alpha or interleukin-2. There are many new immunotherapy's being actively studied for kidney cancer.

Targeted therapy for kidney cancer
This therapy uses drugs or other substances to find and target cancer cells with less toxicity to normal cells. One type of targeted therapy is anti-angiogenic agents. These keep blood vessels from feeding a tumor, causing it to shrink or stop growing. Another type of targeted agent is known as multi kinase inhibitors or tyrosine kinase inhibitors. These are oral drugs that block an enzyme pathway which allows cancer cells to grow. A third type of targeted therapy is known as m-TOR inhibitors. There are two of these drugsvailable, one oral and one by IV. They block a pathway which allows blood vessels to help tumor cells grow. Each of these drugs has a unique place in the management of advanced kidney cancer. e.g -Tacrolimus ( m-TOR inhibitor ), sunitinib, axitinib

Signs and symptoms
Typical signs and symptoms of Wilms' tumor include the following: An abnormally large abdomen Loss of appetite Abdominal pain Fever Nausea and vomiting Blood in the urine (in about 20% of cases) High blood pressure in some cases (especially if synchronous or metachronous bilateral kidney involvement)

Pathogenesis
Most nephroblastoma are on one side of the body only and are found on both sides in less than 5% of cases. They tend to be encapsulated and vascularized tumors that do not cross the midline of the abdomen. In cases of metastasis it is usually to the lung. A rupture of Wilms tumor puts the patient at risk of bleeding and peritoneal dissemination of the tumor. In such cases, surgical intervention by a surgeon who is experienced in the removal of such a fragile tumor is imperative.
Pathologically, a triphasic nephroblastoma comprises three elements: blastema mesenchyme epithelium Wilms' tumor is a malignant tumor containing metanephric blastema, stromal and epithelial derivatives. Characteristic is the presence of abortive tubules and glomeruli surrounded by a spindled cell stroma. The stroma may include striated muscle, cartilage, bone, fat tissue, fibrous tissue. Dysfunction is caused when the tumor compresses the normal kidney parenchyma.
The mesenchymal component may include cells showing rhabdomyoid differentiation or malignancy (rhabdomyosarcomatous Wilms).
Wilms tumors may be separated into 2 prognostic groups based on pathologic characteristics: Favorable -Contains well developed components mentioned above Anaplastic -Contains diffuse anaplasia (poorly developed cells)

Staging
Staging is a standard way to described the extent of spread of wilms tumors and to determine prognosis and treatments.
Staging is based on anatomical finding and cell pathology.

Stage I (43% of patients)
Stage I Wilms tumor, all of the following criteria must be met: Tumor is limited to the kidney and is completely excised. Bilateral renal biopsies and staging of each kidney followed by preoperative treatment with regimen I, followed by second-look surgery and possibly more chemotherapy and/or radiotherapy Diffuse anaplastic 25% 42% Bilateral renal biopsies and staging of each kidney followed by preoperative treatment with regimen I, followed by second-look surgery and possibly more chemotherapy and/or radiotherapy

Prevent Kidney Cancer
It is not clear how to prevent the disease. However, certain factors are linked to kidney cancer, so you can take certain steps to lower your risk -Quit smoking. If you smoke, quit. Many options for quitting exist, including support programs, medications and nicotine replacement products. Tell your doctor you want to quit, and discuss your options together.
Maintain a healthy weight. Work to maintain a healthy weight. If you're overweight or obese, reduce the number of calories you consume each day and try to exercise most days of the week. adults should do a minimum of 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity, such as cycling or brisk walking, every week.
Control high blood pressure, If your blood pressure is high, you can discuss options for lowering your numbers. Lifestyle measures such as exercise, weight loss and diet changes can help. Some people may need to add medications to lower their blood pressure.
Avoid eating foods high in saturated fat because it will increase your cholesterol level. High-fat foods include: meat pies sausages and fatty cuts of meat butter ghee -a type of clarified butter often used in Indian cooking lard cream hard cheese cakes and biscuits foods that contain coconut or palm oil Alcohol, There's evidence to suggest that drinking a moderate amount of alcohol, such as 4-5 glasses of wine a month, will help reduce your risk of developing kidney cancer.

CONCLUSION
1. Renal cancer is a common cancer. 2. Malignant renal tumors are more common compared to benign tumors. 3. Prognosis of renal tumors depends on stage. 4. In adult renal cancer (RCC) surgery remains the main stage of treatment.
Other effective therapy for RCC in metastatic disease is angiogenesis inhibition and biological agent. 5. In childhood renal tumors surgery, chemo and radiation all are effective. 6. Prognosis is good compared to adult RCC. 7. Benign renal tumors are less common and difficult to diagnose. 8. Life style modification can reduce incidence of cancer.