Renal cell carcinoma (RCC) is also known as renal adenocarcinoma, hypernephroma, clear cell carcinoma, and malignant nephroma. It is responsible for approximately 2% of adult malignancies. Male-female ration is 1.5:1. Age at presentation ranges from 50 to 70 years, with a median age at diagnosis of 57 years. Risk factors for RCC inclued tobacco use, long-term phenacetin use, Von Hippel-Lindau disease (VHLD), chronic dialysis, and family history.

Bilateral RCC commonly develops in patients with VHLD, tuberous sclerosis, acquired cystic kidney disease and familial RCC. Bilateral neoplasms occur in less than 2% of patients with sporadic RCC. This tumor may spread via local extension, hematogenously, or by the lymphatic system.

ROBSON CLASSIFICATION FOR STAGING OF RCC:
I - Tumor confined to renal capsule
II - Tumor extends throught renal capsule but is confined
to renal fascia. Ipsilateral adrenal may be involved
in this stage
IIIA - Tumor involves renal vein, IVC, or both
IIIB - Tumor involves regional lymph nodes
IIIC - Tumor involves regional nodes and renal venous structure
IVA - Direct extension of tumor through renal fascia to
involve adjacent organs besides ipsilateral adrenal
IVB - Distant metastases

Treatment options include surgery (radical or partial nephrectomy), angioinfarction (arterial tumor embolization), hormonal therapy (e.g. progestins, antiestrogens, and androgens), chemotherapy, immunotherapy (Interferons), and radiation therapy. Tumor embolization may be used to minimize blood loss during surgery or to produce palliation. Objective tumor regression after treatment with hormonal agents is achieved in less than 6% of patients. Immunotherapy is mainly used in patients with metastatic RCC after resection of primary tumors with successful results in about 20% to 30% of patients with 5% to 10% complete responses. RCC is relatively radioresistant tumor. The role of radiation therapy is primarily in preoperative reduction in the size and fixation of tumors.

CT FINDINGS IN RENAL CELL CARCINOMA
- Most occur in the renal cortex and demonstrate an exophytic growth pattern. They distort the renal contour and larger tumors involve both the renal cortex and medulla. Solid tumors may be hyperdense, hypodense, or hyperdense on non-enhanced CT. Some lesions may appear heterogenous on non-enhanced scans because of hemorrhage and necrosis. Tumor calcification occurs in approximately 30% of cases. They may also rarely demonstrate small amounts of adipose tissue. A combination of fat and calcification shoud suggest RCC because fat-containing AMLs do not usually calcify. Solid RCCs usually demonstrates heterogenous enhancement(>10 HU). 2% to 5% of RCCs are predominantly cystic. Filling defects (clots, tumor thrombus) in the collecting sytem and renal veins may be seen.