Localized malignant peritoneal mesothelioma is a rare tumor with limited information in the literature. In this study, we present our experience with 18 cases seen in our hospital over a period of 43 years (1978 to 2021). Patients’ median age was 55 years (y) (range: 33 to 79 y) and most of them were Caucasians. Patients presented with abdominal pain (11), ascites and right leg swelling (1), abdominal mass (1), and as incidental finding (1). Thirty percent of patients reported asbestos exposure, and all patients with available information had family history of tumors; a third had personal history of tumors. Seventy-seven percent had some form of abdominopelvic surgery and/or inflammatory process. Most cases had microscopic features typically seen in malignant mesothelioma; however, some cases had confounding features such as signet-ring cells, spindle cells, clear cell changes, and adenomatoid tumor-like appearance. BAP-1 by immunohistochemistry was lost in 1/3 cases. Only 1 patient underwent genetic testing and had an MSH2 germline mutation. Homozygous deletion of CDKN2A by FISH was not found in 1 tested case, although next-generation sequencing identified a CDKN2A pathogenic mutation. 16/18 (88%) had surgical treatment, and some also received adjuvant chemotherapy. The mean overall survival (OS) of our patients was 80.4 months (95% confidence interval: 54.3-106.52); the 3-year OS was 79%, while the 5-year OS was 52.6%. Fifty-three percent of patients had recurrences and 20% had tumor progression. Although the limited sample precludes definitive conclusions, small tumor size, low-grade cytology, and low mitotic index appeared to be associated with an indolent behavior.

局限性恶性腹膜间皮瘤是一种罕见的肿瘤，文献资料有限。在这项研究中，我们介绍了我们在 43 年（1978 年至 2021 年）期间在我们医院就诊的 18 例病例的经验。患者的中位年龄为 55 岁（y）（范围：33 至 79 岁），其中大多数是白种人。患者出现腹痛 (11)、腹水和右腿肿胀 (1)、腹部肿块 (1) 和偶然发现 (1)。30% 的患者报告接触过石棉，所有有可用信息的患者都有肿瘤家族史；第三个人有肿瘤病史。77% 的人接受过某种形式的腹盆腔手术和/或炎症过程。大多数病例具有典型的恶性间皮瘤的微观特征；然而，有些病例具有令人困惑的特征，例如印戒细胞、梭形细胞、透明细胞改变和腺瘤样肿瘤样外观。免疫组化BAP-1丢失1/3。只有 1 名患者接受了基因检测，并且MSH2种系突变。尽管下一代测序确定了CDKN2A致病突变，但在 1 个测试病例中未发现 FISH 对CDKN2A的纯合缺失。16/18（88%）接受了手术治疗，部分接受了辅助化疗。我们患者的平均总生存期（OS）为 80.4 个月（95% 置信区间：54.3-106.52）；3 年 OS 为 79%，而 5 年 OS 为 52.6%。53% 的患者出现复发，20% 的患者出现肿瘤进展。虽然有限的样本排除了明确的结论，但小肿瘤大小、低级别细胞学和低有丝分裂指数似乎与惰性行为有关。