Solid renal tumors are predominantly malignant (>90%). Renal cancer comprises approximately 3% of all cancers in the United States (ratio 2:1 males:females) with approximately 12,000 deaths per year. This disease is most common in patients between the ages of 50 and 70 but may be identified in any age group. Renal cell carcinoma (RCC) is the most common form of renal malignancy in adults. RCC is also known as adenocarcinoma or hypernephroma. The tumor can be focal (confined to one region of the kidney) or extend throughout the organ (as seen in this case) . The tumor may be located entirely within the kidney or present as a mass bulging from the renal capsule. 
When a solid renal mass is identified by sonography it is important to extend the examination to include the renal vein and inferior vena cava to evaluate these vessels for the presence of tumor thrombus. If present, tumor thrombus will be identified as a space-occupying mass of medium echogenicity within the vessel. The presence of tumor thrombus increases the probability of metastases to other parts of the body. It is important to indicate to the referring physician whether or not there is tumor thrombus as this will impact the therapeutic management including the surgical approach used to treat the patient.