Metastatic renal cell carcinoma (RCC) to the urinary bladder is rarely seen. Herein, we report the histologic subtypes, immunohistochemical characteristics, and prognosis of 11 patients with metastatic RCC to the urinary bladder. The mean age at the time of diagnosis of metastatic RCC to the bladder was 66 years (range, 58 to 79 y). There were 9 male and 2 female patients. Four patients presented with hematuria, 2 with urinary retention/obstruction, and 1 with bladder calculi. Four patients were asymptomatic and presented for surveillance cystoscopy, wherein they were found to have bladder masses. Nine patients had prior histories of RCC. The remaining 2 patients presented with metastatic clear cell RCC to the bladder and were subsequently found to have renal masses. The average time between nephrectomy and metastasis to the bladder was 20.7 months (range, 0 to 87 mo). Of the 10 patients with radical/partial nephrectomy, 7 cases were clear cell (2 with sarcomatoid features), 2 papillary, and 1 chromophobe with histologic fidelity between the primary and metastasis. Of cases with available data, the primaries' ISUP nucleolar grades were 2 (n=2), 3 (n=4), and 4 for the 2 cases with sarcomatoid features. In 8 cases, the bladder RCC undermined overlying urothelium with extensive urothelial denudation, and in 3 cases the RCC was free floating without attachment to the urothelium. The 1 chromophobe RCC metastasized with pagetoid spread to a preexisting urothelial papilloma. PAX8 immunohistochemistry was used to confirm the diagnosis in 2 cases. Three patients have no evidence of disease (7, 9, and 13 mo). Two are alive with disease after chemotherapy (30, 37 mo). Six patients are dead of disease with multiorgan metastases; 4 are dead after therapy (5, 8, 25, 28 mo), and two died without radiation or chemotherapy at 10 and 71 months. Metastatic RCC to the urinary bladder is uncommon, with most cases clear cell RCC. In some cases, evidence supports "drop metastases" as the mechanism of spread and patients have relatively long survival. However, in other cases spread to the bladder is in the setting of metastases to other sites, and these patients tended to die relatively shortly after their bladder metastases.
肾细胞癌(RCC)转移到膀胱少见。本文报告了11个肾癌转移到膀胱病例的组织学亚型、免疫组化特点和预后。诊断肾细胞癌转移到膀胱时的平均年龄是66岁 (范围, 58 to 79岁)。男性9例，女性2例。4例患者表现为血尿，2例表现为尿储留，1例表现为膀胱结石。4例患者无症状，例行膀胱镜检查时发现膀胱肿物。9例有RCC病史。余下2例有膀胱转移性RCC，随后发现肾肿物。肾切除和发现膀胱转移灶间隔平均时间是20.7个月 (范围, 0 to 87个月)。10例全部/部分肾切除患者, 7例是透明细胞癌 (2例有肉瘤样特点), 2例乳头状癌, 1例嫌色细胞癌，原发灶与转移灶组织学类型相同。原发灶ISUP 核级别是2 (n=2), 3 (n=4), 和 4（2例有肉瘤样特点者）。8例膀胱RCC 破坏被覆尿路上皮，伴有广泛的尿路上皮剥脱。3例RCC瘤细胞漂浮状态，不与尿路上皮粘附。1例嫌色RCC呈派杰样转移到已经存在的尿路上皮乳头状瘤。2例使用PAX8免疫组化用于证实诊断。3例呈无疾病状态 (7, 9,和13个月）。2例化疗后存活 (30, 37 个月)。6例死于多脏器转移，其中4例死于治疗后 (5, 8, 25, 28个月)，2例在未经放化疗10个月和71个月死亡。转移到膀胱RCC少见，大部分病例为透明细胞RCC。一些病例，证据支持“种植”转移，患者有较长时间生存期。而有些转移到膀胱的病例背景是有其它多部位转移，这些患者一般在膀胱转移后短期内死亡。