[Studyon Renal Cell Carcinoma Detected by Abdominal Ultrasonography during Routine Health Check-Up]

We performed a study on renal cell carcinoma (RCC) detected by abdominal ultrasonography during routine health check-up at Sapporo Teishin Hospital. The study included a total of 13,127 ultrasonographic examinations performed on 4,339 patients who visited our hospital for routine health check-ups during a 21- year period from April 1995 to March 2016. RCC was suspected from ultrasonographic findings and later histopathologically diagnosed in 11 patients in this group (detection rate 0.25%). Patients were male, aged 37 to 64 (median, 52.1 years). None of the patients had subjective symptoms, and all were negative for microscopic hematuria. Greatest dimensions of tumors were 18 to 40 mm (mean, 28 mm) ; anechoic rims, which are a characteristic ultrasonographic finding in RCC, were identified in 8 patients (72. 7%), intratumoral cysts were identified in 8 patients (72.7%), and protrusions from the surface of the kidney were identified in 9 patients (81. 8%). Regarding vascular distribution of renal tumors during Doppler ultrasonography, peripheral patterns or mixed penetrating and peripheral patterns were identified in 100% of cases (8/8). All 11 patients were diagnosed histopathologically with clear cell renal cell carcinoma, and the histological grade was G1 in 6 patients, G1＞G2, in 1 patient G2＞G1, in 1 patient and G2 in 3 patients. All 11 tumors were classified as pT1a pathological stage according to the TNM classification, and no regional lymph node metastases or distant metastases were identified. We consider that ultrasonography plays an integral role in the early detection of RCC during check-ups and examinations.