恶性腹膜间皮瘤（MPeM）是一种罕见的癌症，晚期预后不良，无法手术的患者的标准一线治疗是化疗。尽管将程序性细胞死亡1（PD-1）抑制剂与化疗相结合在几种恶性实体肿瘤中通常被认为是安全和有效的，但关于初级免疫化疗在晚期MPeM中的报道很少。在此，据我们所知，我们呈现了一个上皮样亚型MPeM的治疗委员会，该患者是治疗原始者，并且由于初始PD-1抑制剂加标准化疗而得到了延长的无进展生存期（PFS）和良好的耐受性。一个49岁的男性因腹部持续灼烧感被送入我们医院就诊。计算机断层扫描显示腹下部有一个实质性肿块，后经过核心针穿刺活检被诊断为上皮样亚型MPeM。患者接受了8个周期的培美曲塞800毫克（第1天），顺铂60/50毫克（第1-2天）和雷伐替尼（PD-1抑制剂）240毫克（第1天），每3周一次。他在腹膜肿瘤方面取得了显著的缩小，并且症状明显改善。最佳肿瘤反应是部分缓解，最终PFS为7个月。在联合治疗过程中没有发生免疫相关的不良反应。本病例的结果证明了免疫化疗在未手术的MPeM治疗中有希望的抗肿瘤活性。© 2023年作者。Baishideng Publishing Group Inc.出版权所有。

Malignant peritoneal mesothelioma (MPeM) is a rare cancer with a poor prognosis at advanced stage, and the standard first-line treatment for inoperable patients is chemotherapy. Although combining programmed cell death 1 (PD-1) inhibitors with chemotherapy is generally considered safe and effective in several malignant solid tumors, there are few reports regarding initial immunochemotherapy in advanced MPeM.Here, to our knowledge, we present the first case of a patient with epithelioid subtype MPeM, who was treatment-naïve and benefited from initial PD-1 inhibitor plus standard chemotherapy with a prolonged progression-free survival (PFS) and good tolerance. A 49-year-old man was admitted to our hospital for a persistent burning sensation in the abdomen. Computed tomography revealed a solid mass in the lower abdomen, which was subsequently diagnosed histologically as epithelioid subtype MPeM by core needle biopsy. The patient received eight cycles of pemetrexed 800 mg (day 1), cisplatin 60/50 mg (day 1-2), and zimberelimab (PD-1 inhibitor) 240 mg (day 1) every 3 wk. He achieved significant reduction of peritoneal tumors with remarkable improvement in symptoms. The best tumor response was partial remission with a final PFS of 7 mo. No immune-related adverse event occurred during the combination treatment.The outcome of the present case demonstrates the promising anti-tumor activity of immunochemotherapy to treat inoperable MPeM in the future.©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.