目的：探讨膀胱原发性上皮样血管肉瘤（epithelioid angiosarcoma, EA）患者的临床病理学特征、诊断与鉴别诊断、生物学行为、预后以及治疗方式的选择。方法：分析1例膀胱原发性EA患者的临床表现、组织学特征、免疫组织化学（免疫组化）检测结果及随访情况，并在PubMed上检索1998年至2021的相关文献，对完整的17例EA病例进行归纳总结。结果：膀胱原发性EA（以下简称EA）罕见，18例EA患者中，男性多于女性（男∶女为15∶3），中位发病年龄为65岁（32~85岁），8例患者（8/18）有明确的骨盆放疗史，多数患者短期内局部肿瘤复发，并出现肿瘤远处转移，随访中12例患者（12/18）死亡，中位生存时间仅6个月（5周~19个月），6例患者（6/18）带病或无病生存，随访时间从3个月到32个月不等。肿瘤细胞在光学显微镜下呈弥漫片状、血窦样排列，可见肿瘤细胞形成的空泡状单细胞性血管腔，背景广泛出血，细胞多边形，呈上皮样，胞质嗜双色性，细胞核大，核分裂象易见，可见病理性核分裂象。免疫组化检测结果显示，肿瘤细胞Vimentin、CD31、CD34、ERG、Fli-1和CK-P阳性，CK7部分阳性，Ki-67热点区约40%。结果：膀胱原发性EA罕见，部分患者有骨盆放疗病史，高度恶性，目前尚无有效的治疗方式，预后不良，根治性手术联合放化疗等多种治疗方式的选择有可能延长患者的生存期。因为细胞角蛋白的免疫组化染色阳性，膀胱原发性EA容易被误诊为高级别癌，需要与放疗后肉瘤、肉瘤样癌、假血管肉瘤样尿路上皮癌、上皮样血管内皮瘤等鉴别诊断。

Objective: To investigate the clinicopathological characteristics, diagnosis, differential diagnosis, biological behavior, prognosis, and treatment options of patients with primary epithelioid angiosarcoma(EA) of the bladder. Methods: The clinical manifestations, histological features, immunohistochemistry results and follow-up of a case of primary EA of the bladder were analyzed：Relevant literature from 1998 up to 2021 were searched on PubMed， and 17 cases with relatively complete clinical and follow-up data reported in the literature were summarized. Results: Primary EA of the bladder is rare, males tend to occur (male: female, 15∶3), the median age at presentation was 65 years (range, 32-85 years), and 8 patients (8/18 cases)(44.4%) had a clear history of radiotherapy to the pelvis. Most of them had local recurrence and distant metastasis within a short period of time. During follow-up 12 of the 18 cases (66.7%) died of disease, with a median survival of 6 months (range, 5 weeks to 19 months), 6 of 18 cases (33.3%) survived with or without disease, the follow-up time ranged from 3 months to 32 months. Histologically, the tumors were composed of sheets and sinusoid of highly atypical epithelioid cells. Tumor cells were pleomorphic with amphophilic cytoplasm. Mitotic activity was high and pathological mitotic could be seen. Intracytoplasmic lumens or vacuoles were present with occasional red blood cell within the vacuole. A hemorrhagic background was present. Immunostaining was positive for Vimentin, CD31, CD34, ERG, Fli-1 and CK-P, with partly positivity for CK7, Ki-67 hot spot about 40%. Conclusions: Bladder primary EA is rare. Some patients have a history of pelvis radiotherapy and are highly malignant. The therapentic effect and prognosis are not satisfied. Radical surgery combined with radiotherapy and chemotherapy and other treatment options may prolong survival. Because the immunohistochemical staining of cytokeratin is positive, it is easy to be misdiagnosed as high-grade cancer. It needs to be differentiated from post-radiotherapy sarcoma, sarcomatoid carcinoma, pseudoangiosarcomatoid urothelial carcinoma, epithelioid hemangioendothelioma, et al.