Renal cell carcinoma, also known by a gurnistical tumor, is the most common form of kidney cancer arising from the renal tubule. It is the most common type of kidney cancer in adults. Initial treatment is surgery. It is notoriously resistant to radiation therapy and chemotherapy, although some cases respond to immunotherapy. The advent of targeted cancer therapies such as sunitinib has vastly improved the outlook for treatment of RCC.

Signs and symptoms
Renal cell carcinoma affects about three in 10,000 people, resulting in about 31,000 new cases in the US per year. Every year, about 12,000 people in the US die from renal cell carcinoma. It is more common in men than women, usually affecting men older than 55.
Why the cells become cancerous is not known. A history of smoking greatly increases the risk for developing renal cell carcinoma. Some people may also have inherited an increased risk to develop renal cell carcinoma, and a family history of kidney cancer increases the risk.
People with von Hippel-Lindau disease, a hereditary disease that also affects the capillaries of the brain, commonly also develop renal cell carcinoma. Kidney disorders that require dialysis for treatment also increase the risk for developing renal cell carcinoma.

Causes
Gross examination shows a hypervascular lesion in the renal cortex, which is frequently multilobulated, yellow (because of the lipid accumulation) and calcified.
Light microscopy shows tumor cells forming cords, papillae, tubules or nests, and are atypical, polygonal and large. Because these cells accumulate glycogen and lipids, their cytoplasm appear "clear", lipid-laden, the nuclei remain in the middle of the cells, and the cellular membrane is evident. Some cells may be smaller, with eosinophilic cytoplasm, resembling normal tubular cells. The stroma is reduced, but well vascularized. The tumor grows in large front, compressing the surrounding parenchyma, producing a pseudocapsule.
Secretion of vasoactive substances (e.g. renin) may cause arterial hypertension, and release of erythropoietin may cause polycythemia (increased production of red blood cells).

Pathology
The characteristic appearance of renal cell carcinoma (RCC) is a solid renal lesion which disturbs the renal contour. It will frequently have an irregular or lobulated margin. 85% of solid renal masses will be RCC. 10% of RCC will contain calcifications, and some contain macroscopic fat (likely due to invasion and encasement of the perirenal fat). Following intravenous contrast administration (computed tomography or magnetic resonance imaging), enhancement will be noted, and will increase the conspicuity of the tumor relative to normal renal parenchyma.
A list of solid renal lesions includes:
In particular, reliably distinguishing renal cell carcinoma from an oncocytoma (a benign lesion) is not possible using current medical imaging or percutaneous biopsy.
Renal cell carcinoma may also be cystic. As there are several benign cystic renal lesions (simple renal cyst, hemorrhagic renal cyst, multilocular cystic nephroma, polycystic kidney disease), it may occasionally be difficult for the radiologist to differentiate a benign cystic lesion from a malignant one. A famous radiologist named Dr. Morton Bosniak developed a classification system for cystic renal lesions that classifies them based specific imaging features into groups that are benign and those that need surgical resection.
Percutaneous biopsy can be performed by a radiologist using ultrasound or computed tomography to guide sampling of the tumor for the purpose of diagnosis. However this is not routinely performed because when the typical imaging features of renal cell carcinoma are present, the possibility of an incorrectly negative result together with the risk of a medical complication to the patient make it unfavorable from a risk-benefit perspective.This is not completely accurate, there are new experimental treatments.

renal cell carcinoma
metastasis from an extra-renal primary neoplasm
renal lymphoma
squamous cell carcinoma
juxtaglomerular tumor (reninoma)
transitional cell carcinoma
angiomyolipoma
oncocytoma
Wilm's tumor Radiology
If it is only in the kidneys, which is about 40% of cases, it can be cured roughly 90% of the time with surgery. If it has spread outside of the kidneys, often into the lymph nodes or the main vein of the kidney, then it must be treated with chemotherapy and other treatments.

Treatment
Surgical removal of all or part of the kidney (nephrectomy) is recommended. This may include removal of the adrenal gland, retroperitoneal lymph nodes, and possibly tissues involved by direct extension (invasion) of the tumor into the surrounding tissues. In cases where the tumor has spread into the renal vein, inferior vena cava, and possibly the right atrium (angioinvasion), this portion of the tumor can be surgically removed, as well. In case of metastases surgical resection of the kidney ("cytoreductive nephrectomy") may improve survival, as well as resection of a solitary metastatic lesion.

Surgery
Percutaneous, image-guided therapies, usually managed by radiologists, are being offered to patients with localized tumor, but who are not good candidates for a surgical procedure. This sort of procedure involves placing a probe through the skin and into the tumor using real-time imaging of both the probe tip and the tumor by computed tomography, ultrasound, or even magnetic resonance imaging guidance, and then destroying the tumor with heat (radiofrequency ablation) or cold (cryotherapy). These modalities are at a disadvantage compared to traditional surgery in that pathologic confirmation of complete tumor destruction is not possible.

Percutaneous therapies
Radiation therapy is not commonly used for treatment of renal cell carcinoma because it is usually not successful. Radiation therapy may be used to palliate the symptoms of skeletal metastases.

Medications
Chemotherapy may be used in some cases, but cure is unlikely unless all the cancer can be removed with surgery.

Chemotherapy
In November 2006, it was announced that a vaccine had been developed and tested with very promising results.(See [3]) The new vaccine, called TroVax, works in a totally different way to existing treatments by harnessing the patient's own immune system to fight the disease. Experts say this suggests that gene therapy vaccines could prove an effective treatment for a whole range of cancers. Oxford BioMedica[4] is the company behind the vaccine; it's a British company established as a spin-out from Oxford University and specialises in the development of gene-based treatments. Further vaccine trials are underway.

Prognosis

Stauffer syndrome