[Clinical and pathological studies on incidental renal cell carcinoma]

During the five-year period from 1985 to 1989, a total of 69 patients with renal cell carcinoma received treatment at Daisan Hospital of Jikei University School of Medicine. Among these patients, there were 23 patients (33.3%) with incidental renal cell carcinoma. These 23 cases were studied clinically and pathologically in comparison with 46 symptomatic cases. The tumor was detected by ultrasonography (US) or computed tomography (CT) conducted for the diagnosis of other diseases in 16 cases and by US included in the battery of physical examinations in the remaining 7 cases. As compared to symptomatic cases, less hematological abnormalities were found in these cases, since ESR was accelerated in only 2 cases and anemia and elevation in alpha 2-globulin level were found in none of the cases. As for diagnostic imaging, CT could detect the tumor in all of 23 cases and US in 20 out of 21 cases. Intravenous pyelography gave normal pyelograms in 4 cases. Normovascular findings were obtained by renal angiography in 2 cases. The mean largest diameter of tumors of these 23 cases was 3.9 cm, being smaller than the corresponding mean diameter of 7.7 cm for symptomatic cases. In 8 out of 23 cases tumors were small renal cell carcinoma of 2.5 cm or less in diameter. Pathologically, incidental renal cell carcinoma was characterized by small size, expansive growth pattern (INF alpha in 18 cases and INF beta in 5 cases) and prevalence of clear cell subtype (clear cell subtype in 18 cases, granular cell subtype in 2 cases and mixed cell subtype in 3 cases).(ABSTRACT TRUNCATED AT 250 WORDS)