孤発性の膀胱転移を来たした嫌色素性腎細胞癌の1例

Abstract

Bladder metastasis of renal cell carcinoma (RCC) is relatively rare, and only 43 cases have been reported in the Japanese literature. In most cases, the histology of the primary site was clear cell type. Here, we report a case of bladder metastasis of chromophobe RCC. A 74-year-old man presented with asymptomatic gross hematuria. He had a history of chromophobe RCC treated with radical nephrectomy 11 years previously. Since cystoscopy revealed a papillary pedunculated tumor, he underwent transurethral resection of the bladder tumor (TUR-Bt). The pathological diagnosis was chromophobe RCC because the histological findings were similar to those of nephrectomized specimens. Four years after TUR-Bt, the patient received bacillus Calmette-Guérin (BCG) therapy under the diagnosis of carcinoma in situ of urothelial cancer of the bladder but not chromophobe RCC. There was no recurrence of chromophobe RCC within 5 years follow-up after TUR-Bt. To the best of our knowledge, there has been only one other case report of bladder metastasis of chromophobe RCC in the Japanese literature.