Ultrasound and CT
Kidney tumors are diagnosed mainly by abdominal ultrasound and CT. Ultrasound findings showing solid masses in the kidneys should be examined by CT with contrast. This will verify renal cell carcinoma and also provide information about the function and morphology of the contralateral kidney. Abdominal CT will determine the extent of the primary tumor and can give information about extrarenal conditions such as vein invasion, enlarged lymph nodes, and the adrenal glands and liver. Chest CT is the most accurate examination to evaluate the condition of the lungs. If this is not performed, a routine X-ray must be carried out to evaluate possible metastases.
MRI is reserved primarily for patients with locally advanced disease, possible vein involvement, renal insufficiency, or allergy to intravenous contrast agent. MRI is used to evaluate inferior caval vein tumor thrombosis, as well as unclassified renal masses.
The physical examination has a limited role in diagnosing renal cell carcinoma. The examination may be useful for identifying palpable masses, palpable cervical lymphadenopathy, bilateral edema in the legs, and recent varicocele in men. Such findings indicate the need for further investigation.
The most common parameters measured are Hb, ESR, alkaline phosphatase, serum calcium, creatinine, and urea.
Collective kidney function and percent of kidney function is determined by renography with GFR. Urography alone is not a reliable measurement of function of the contralateral kidney.
The kidneys are easily accessible for percutaneous biopsies. Radiologically-guided or ultrasound-guided biopsy is very exact and provides information about possible malignancy. In 10-20% of cases, biopsies are inconclusive.
Due to clinical findings, laboratory tests, and/or symptoms, other diagnostic procedures may be necessary. Bone scan, CT, or MRI of the brain may be necessary. Renal arteriography, venography, or fine needle aspiration play a limited role in clinical evaluation of patients with renal cell carcinoma, but should be considered in some cases.