Sonographic appearances of Renal Cell Carcinoma: a review of 78 patients

Renal cell carcinoma (RCC) is the most common malignant renal tumor in adults. The kidney can usually be adequately imaged with real-time ultrasound (US) scanners. To summarize the ultrasonographic manifestations of RCC, we reviewed 78 patients with pathologically proved RCC. Within a per iod of 5 years , sevent y-eight patients were found to have renal masses by ultrasonography (US) study of upper abdomen, and subsequently underwent surgical treatment and/or biopsy. Histopathological study confirmed the diagnosis of RCC in all patients. Thirty-five of them were asymptomatic and were found to have renal tumor incidentally at US examination. The US studies were reviewed to clarify the relationship between echopatterns and sizes of RCC. The echogenicity of the lesions was graded from I through V as compared to the echogenicity of renal medulla, renal cortex, liver/spleen and renal sinus. Most RCCs were presented as solid masses (n= 33; 42%) or complex masses (n= 42; 54%). Only 3 pat ients were presented with cyst ic masses (4%). Grade I echogenicity (not higher than renal medulla) was noted in only 5% of renal tumors; grade II (higher than medulla but not higher than renal cortex) in 35%; grade III (higher than cortex but not higher than liver/spleen) in 50%; and grade IV (not higher than renal sinus) in 10%. Small RCCs ( 3cm) tended to be relatively homogeneous in echogenicity and ranged from grade II to III echogenicity. RCCs with a size between 3cm and 5 cm were relatively heterogeneous in echogenicity and had grade II to IV echogenicity. RCCs sized between 5cm and 7cm were frequently complex masses. RCCs with grade IV echogenicity were rare (10%), and cystic RCCs were noted in 4% of the patients. US is a cost-effective, easily available, portable, and non-radiating examination for kidneys. It can be used as a screening modality for renal cancer. In patients with inconclusive US imaging finding or clinically high suspicion of focal renal tumor, CT, MRI, or even angiography should be utilized as complementary diagnostic modalities.