Localized Malignant Peritoneal Mesothelioma (LMPeM) in Women: A Clinicopathologic Study of 18 Cases

Abstract

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.

NR4A3 fusions characterize a distinctive peritoneal mesothelial neoplasm of uncertain biological potential with pure adenomatoid/microcystic morphology

“…Adenomatoid features are much less common in peritoneal mesothelioma 3–5 . A review of the literature reveals seven cases of peritoneal mesothelial neoplasms reported as adenomatoid mesothelioma, microcystic mesothelioma, or multifocal mesothelial adenomatoid tumors 55–61 .…”

“…54 Adenomatoid features are much less common in peritoneal mesothelioma. [3][4][5] A review of the literature reveals seven cases of peritoneal mesothelial neoplasms reported as adenomatoid mesothelioma, microcystic mesothelioma, or multifocal mesothelial adenomatoid tumors. [55][56][57][58][59][60][61] However, some of these cases were associated with conventional mesothelioma component, 55 and accompanying genetic analysis was not described.…”

“…The etiology and molecular pathogenesis of mesothelioma is variable and is dependent on anatomic site. While most pleural cases are associated with occupational asbestos exposure, 1,2 this is true for only a minority of peritoneal tumors, especially those tumors occurring in the peritoneum of women 1–5 . Recent next generation sequencing studies have shown highly heterogeneous mutational profiles in mesothelioma 6–10 .…”

“…While most pleural cases are associated with occupational asbestos exposure, 1,2 this is true for only a minority of peritoneal tumors, especially those tumors occurring in the peritoneum of women. [1][2][3][4][5] Recent next generation sequencing studies have shown highly heterogeneous mutational profiles in mesothelioma. [6][7][8][9][10] Moreover, inactivation of the BRCA1-associated protein-1 (BAP1) has recently emerged as a frequent molecular event in 60%-80% of mesotheliomas.…”

Clear-Cell Mesothelioma of Uterine Corpus: Diagnostic Challenges in Intraoperative Frozen Sections

“…This figure and Figure 2 demonstrate the macroscopic and microscopic appearance of clear-cell mesothelioma that has led to the intraoperative diagnosis of clear-cell adenocarcinoma. The occurrence of extragenital clear-cell adenocarcinoma, although uncommon, could be expected, as clear-cell adenocarcinoma is common in the Eastern world, accounting for up to 27% of ovarian epithelial cancers in Japan [ 6 ], and this tumor can arise from non-ovarian endometriosis. While the diagnosis of clear-cell adenocarcinoma in the endometrium or the ovary may not require or depend on immunohistochemistry, the diagnosis of clear-cell adenocarcinoma of peritoneal origin needs to be supported by an appropriate and extensive immunohistochemical panel.…”