一名 76 岁男性被诊断患有膀胱憩室尿路上皮癌 (UC)，被转诊至我们机构。该患者被诊断患有肌层浸润性膀胱癌，磁共振成像显示肿瘤侵入憩室周围的脂肪组织，证实了这一点。经过两个周期的吉西他滨和顺铂新辅助治疗后，他接受了机器人辅助根治性膀胱切除术 (RARC) 和盆腔淋巴结清扫术，然后进行体内回肠导管。膀胱肿瘤的组织病理学诊断为具有鳞状分化和肉瘤样亚型的 UC，且 ypT3bN0M0 无阳性手术切缘。患者拒绝任何辅助治疗。 RARC 六个月后，患者因突然出现全身疼痛而到访我们的机构。由于 18F-氟脱氧葡萄糖正电子发射断层扫描-CT 显示多处转移，包括骨、主动脉旁淋巴结和胸膜，因此开始将派姆单抗作为二线治疗。帕博利珠单抗两个疗程后，患者症状明显改善，PET-CT上异常的全身蓄积几乎消失。经过 26 个月的派姆单抗连续治疗后，患者保持无病状态。据报道，多项研究重点关注肿瘤亚型和程序性细胞死亡配体 1 (PD-L1) 阳性肿瘤细胞作为与派姆单抗疗效相关的候选生物标志物。与纯 UC 相比，肉瘤样亚型中 PD-L1 阳性细胞的比例较高，可能会带来良好的肿瘤学结果。版权所有 © 2024，Murase 等人。

A 76-year-old man who was diagnosed with urothelial carcinoma (UC) in the bladder diverticulum was referred to our institution. The patient was diagnosed with muscle-invasive bladder cancer, which was confirmed by magnetic resonance imaging that showed tumor invasion into the fatty tissue surrounding the diverticulum. After two cycles of neoadjuvant gemcitabine and cisplatin, he underwent robot-assisted radical cystectomy (RARC) with pelvic lymph node dissection followed by intracorporeal ileal conduit. The histopathologic diagnosis of the bladder tumor was UC with squamous differentiation and sarcomatoid subtype and ypT3bN0M0 without positive surgical margins. The patient refused any adjuvant therapy. Six months after RARC, the patient visited our institution with a complaint of suddenly occurring generalized pain. Because 18F-fluorodeoxyglucose positron emission tomography-CT showed multiple metastases, including bone, para-aortic lymph nodes, and pleura, pembrolizumab was initiated as a second-line treatment. After two courses of pembrolizumab, the patient's symptoms remarkably improved, and the abnormal systemic accumulation on PET-CT almost disappeared. After 26 months of continuous treatment with pembrolizumab, the patient remains disease-free. Several studies have been reported that focused on tumor subtypes and programmed cell death ligand 1 (PD-L1)-positive tumor cells as candidate biomarkers in relation to the efficacy of pembrolizumab. The higher proportion of PD-L1-positive cells in the sarcomatoid subtype may have resulted in favorable oncological outcomes compared with pure UC.Copyright © 2024, Murase et al.