Clinicopathological characteristics of primary peritoneal epithelioid mesothelioma of clear cell type: A case report

Our plain-English summary of Clinicopathological characteristics of primary peritoneal epithelioid mesothelioma of clear cell type: A case report, by X.M. Du, Y.P. Wei, Y. Gao, et al (Medicine, 2021).

The study

• Authors: X.M. Du, Y.P. Wei, Y. Gao, Z. Li, J.M. Zhang, H. Chang, Y. Li
• Journal: Medicine
• Published: 2021;100(12):e25264
• Type of article: Case report
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Rationale: Primary peritoneal epithelioid mesothelioma of clear cell type is an extremely rare entity composed of clear cytoplasm. It is challenging to diagnose because of the morphological resemblance to clear cell tumor.

Patients Concerns: A 69-year-old male patient had swollen lymph nodes in the right inguinal region for 7 months and was constipated for 1 month.

Diagnosis: The patient was diagnosed as peritoneal epithelioid mesothelioma of clear cell type based on computed tomography scan, pathology, immunohistochemistry, special staining and whole-exome sequencing. This patient harbored VHL gene alteration in exon 1 and homologous recombination defect (with a score of 45). This finding indicated that this patient might be sensitive to platinum-based therapy and Poly ADP-ribose Polymerase (PARP) inhibitor. This patient carried no microsatellite instability, a low level of tumor mutation burden, and a high extent of intratumoral heterogeneity. Eighteen neoantigens were detected.

Interventions: The patient received surgery-based multidisciplinary treatment by integrating cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). HIPEC was administered with docetaxel 120 mg plus cisplatin 120 mg, at 43°C, for 60 minutes. After operation, the patient received intravenous (IV) chemotherapy with docetaxel 60 mg, pemetrexed 750 mg and cisplatin 100 mg, and then intraperitoneal (IP) chemotherapy with docetaxel 40 mg. The patient received interventional therapy of hepatic artery embolization for 5 times.

Outcomes: Regular follow-up was performed until Oct 14, 2020. The patient died 31.6 months later owing to incomplete intestinal obstruction.

Lessons: Primary peritoneal epithelioid mesothelioma of clear cell type needs to be differentiated from a variety of clear cell tumors. This disease is characterized by specific genetic alteration. Whole-exome sequencing contributes to guide individualized therapy. CRS-HIPEC helps achieve long-term overall survival.

Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.

In plain English

This article was a case report of one 69-year-old man, treated at Beijing Shijitan Hospital in China, who was diagnosed with primary peritoneal epithelioid mesothelioma of clear cell type. The report stated that he had a history of asbestos exposure and a family history of cancer. It gave no details of the exposure. He had swollen lymph nodes in the right groin for 7 months. The diagnosis rested on CT scans, microscope examination, tissue staining and whole-exome sequencing. Tumor cells stained strongly for cytokeratins, vimentin, D2-40 and WT-1, and focally for calretinin. Sequencing found a VHL gene alteration in exon 1 and a homologous recombination defect score of 45. The authors said this score indicated sensitivity to platinum-based chemotherapy and PARP inhibitors. He received no targeted therapy. Treatment included cytoreductive surgery with heated intraperitoneal chemotherapy, further chemotherapy and five hepatic artery embolizations. He died on October 14, 2020 of incomplete intestinal obstruction. The authors gave his overall survival as 31.6 months. The authors concluded that this tumor needs to be distinguished from a variety of clear cell tumors.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient), with a table of previously published cases
• Who was studied: One 69-year-old male patient with primary peritoneal epithelioid mesothelioma of clear cell type, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; treated 2018 to 2020
• Exposure: A history of asbestos exposure is stated, with no fiber type, job, product or dose given; the patient also had a family history of cancer
• Main results:
  • At surgery, the peritoneal cancer index (PCI) score was 24
  • Tumor cells stained diffusely and strongly for cytokeratins, vimentin, D2-40, WT-1 and INI-1
  • Tumor cells were focally positive for calretinin, and the Ki67 index was 20%
  • Sequencing of the tumor found a VHL gene alteration in exon 1 (c.254dupT)
  • The patient's homologous recombination defect (HRD) score was 45, which the authors said indicated sensitivity to platinum-based chemotherapy and PARP inhibitors
  • The tumor showed microsatellite stabilization and a low tumor mutation burden (1.13 mutations per Mb in Table 5)
  • Eighteen neoantigens were detected
  • The patient's MATH value was 120.13, which the authors classed as high intratumoral heterogeneity
  • The patient received no targeted therapy
  • The patient died on October 14, 2020 of incomplete intestinal obstruction; overall survival was given as 31.6 months
  • In the authors' table of 8 published cases of this tumor type (including this one), the male to female ratio was 6:2
• The authors' conclusion: The authors concluded that primary peritoneal epithelioid mesothelioma of clear cell type is extremely rare and needs to be distinguished from a variety of clear cell tumors. They added that positive HRD indicates sensitivity to platinum-based chemotherapy and PARP inhibitors.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Epithelioid, Mesothelioma, Pathology, Immunohistochemistry, Microsatellite Instability (MSI-H), Cytoreductive Surgery, HIPEC, Cisplatin.

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• Hormonal Status May Contribute to Sex-Based Survival Differences in Epithelioid Peritoneal Mesothelioma — K.C. Cummins, O. Sears, et al. (2026)
• Dynamic evolution of NK cells and immune remodeling mediated by CRS + HIPEC: prognostic mechanisms and therapeutic implications for malignant peritoneal mesothelioma — Y.T. Liu, Q.D. Zhao, et al. (2025)
• Outcomes of multicystic peritoneal mesothelioma treatment with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy — A. Zahid, L. Clarke, et al. (2021)
• Unresectable peritoneal metastasis treated by pressurized intraperitoneal aerosol chemotherapy (PIPAC) leading to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy — M. Alyami, F. Mercier, et al. (2021)
• Laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for limited peritoneal metastasis. The PSOGI international collaborative registry — A. Arjona-Sanchez, O. Aziz, et al. (2021)

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