[Study on small renal cell carcinoma diagnosed by ultrasonography].

Sixty-seven patients underwent a resection of renal cell carcinoma in our hospital between July 1984 and Mar. 1989. Out of them 31 patients with small renal cell carcinoma less than 4 cm in diameter were examined. The proportion of small renal cell carcinoma to all renal cell carcinoma was 36% (14 patients) in the first half period (July 1984-July 1987) and 61% (17 patients) in the last half (Aug. 1987-Mar. 1989), i.e. in total more than half of all the carcinomas. The patients diagnosed by ultrasonographic screening were 25 (80%) out of the 31 patients. The incidence of small renal cell carcinoma was 4 (0.06%) out of 6892 patients in our health check-up center and 6 (1.0%) out of 610 hemodialysis patients, and they were found by ultrasonic examination. The carcinoma was protruded from the renal contour in 24 patients (77%) and was inside the renal parenchyma (23%) in 7 patients. The carcinoma in the 24 patients was associated with the deformity of its outline. The patients with a positive IVP were 5 out of 31 patients and the carcinoma in 4 out of the 5 patients was inside the renal parenchyma. Of all patients with protrusion of te renal contour, only one patient was with a positive IVP. The above findings indicate that ultrasonic examination is a useful method for the early diagnosis of small renal cell carcinoma.