Clinical and pathological observation of conversion therapy for malignant peritoneal mesothelioma: a case report and literature review

Our plain-English summary of Clinical and pathological observation of conversion therapy for malignant peritoneal mesothelioma: a case report and literature review, by M. Deng, X. Zhang, C. Xu, et al (Pathology Oncology Research, 2023).

The study

• Authors: M. Deng, X. Zhang, C. Xu, R. Luo, L. Chen, Y. Zhou, Y. Hou
• Journal: Pathology Oncology Research
• Published: 2023;29:1611577
• Type of article: Review, Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant mesothelioma (MM) is a tumor originating from the pleura, peritoneum, or pericardial cavity. It is divided into diffuse and localized malignant mesothelioma, with four subtypes in diffuse MM: epithelioid, sarcomatoid, desmoplastic, and biphasic, with biphasic being less common. The onset of this tumor is insidious, and the prognosis is extremely poor in some cases, with a median survival of 6-18 months and no standard treatment options in the past. Aims: We report a case of peritoneal malignant mesothelioma that was successfully treated with transformative therapy. We also review the literature in the hope of providing reference for the treatment and pathological diagnosis of such patients. Methods: The case of the peritoneal malignant mesothelioma was processed and reported in the routine manner for biopsy specimens at different stages. Results and conclusion: We report a case of a malignant tumor originating in the hepatorenal recess, which was diagnosed as biphasic malignant mesothelioma through a biopsy. Immunohistochemical testing showed PD-L1 expression. After multidisciplinary discussion, the patient received transformative treatment, including a trial of combined immunotherapy. The tumor significantly shrank, and the patient obtained a chance for curative surgical resection. Microscopic examination showed significant collagenization in the lesion area, with almost no residual tumor. After 19 months of comprehensive treatment, the patient developed multiple fluffy opacities under the pleura of both lungs. Transthoracic core needle biopsy under CT guidance, the pathology showed organizing pneumonia, considering it as delayed interstitial pneumonitis due to immunotherapy based on previous treatment history. Successful comprehensive treatment was achieved for this case of peritoneal malignant mesothelioma, and the patient has been alive without evidence of disease for 33 months, with long-term follow-up. In this process, the pathologist had three opportunities for pathological diagnosis, which required understanding the patient's medical history, being attentive to the clinical purpose of the specimen, and providing accurate responses to morphological changes at different stages, along with corresponding descriptions and diagnoses to provide effective information for clinical treatment.

Copyright © 2024 Deng, Zhang, Xu, Luo, Chen, Zhou and Hou.

In plain English

This article was a case report with a short literature review from a hospital in Shanghai, China. It described a 61-year-old man with no history of asbestos exposure, admitted in October 2020 after a liver mass was found at a physical examination. A biopsy was diagnosed as biphasic malignant peritoneal mesothelioma involving several sites, including the peritoneum and liver. He received six cycles of pembrolizumab plus cisplatin and four cycles of pembrolizumab alone, after which CT showed the lesions had shrunk. He then had surgery to remove the peritoneum and part of the liver, with heated chemotherapy inside the abdomen. In the removed tissue, residual tumor cells were less than 5%. Immunotherapy continued for 22 cycles in total. In 2022 a lung biopsy showed organizing pneumonia, which the authors considered grade I PD-1-related immune pneumonia, and immunotherapy was stopped. No recurrence or metastasis was seen through July 2023. The authors concluded that the combined treatment achieved good results in this case, but that PD-1-related immune pneumonia needs attention.

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 of one patient, with a narrative literature review in the discussion
• Who was studied: One 61-year-old man admitted to Zhongshan Hospital, Fudan University, Shanghai, on 30 October 2020 after a liver mass was found at a physical examination; followed until 26 July 2023
• Exposure: The patient had no history of asbestos exposure. The report concerns treatment: pembrolizumab with cisplatin, then pembrolizumab alone, followed by total peritonectomy, partial hepatectomy and hyperthermic intraperitoneal chemotherapy (cisplatin and doxorubicin)
• Main results:
  • The biopsy was diagnosed as malignant mesothelioma of biphasic type
  • In the patient's tumor cells, PD-L1 was positive in 70% with clone 28-8, in 70% with clone E1L3N, and in 5% with clone 22C3
  • After six cycles of pembrolizumab plus cisplatin and four cycles of pembrolizumab, CT showed the lesions had shrunk (to 43 mm × 27 mm; the largest lesion had measured 85 mm × 57 mm at diagnosis)
  • In the surgical specimen, residual tumor cells were less than 5%
  • PD-1 immunotherapy continued until 9 May 2022, for a total of 22 cycles
  • A CT-guided lung biopsy in June 2022 showed organizing pneumonia, which the authors considered PD-1-related immune pneumonia, grade I. Immunotherapy was stopped and olaparib was given
  • No recurrence or metastasis was observed through follow-up to 26 July 2023
• The authors' conclusion: The authors concluded that combining neoadjuvant chemotherapy and immunotherapy with surgery and HIPEC achieved good treatment results in this case of malignant peritoneal mesothelioma, but that attention should be paid to PD-1-related immune pneumonia
• Limitations the authors state:
  • The authors stated that it was difficult to evaluate whether tumor remained after treatment, and that there is no established experience in assessing pathological remission in malignant mesothelioma

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Mesothelioma, Pleura, Peritoneum, Pericardial, Localized Malignant Mesothelioma, Epithelioid, Sarcomatoid.

Related studies

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• Clinical picture, response to therapy, and survival of women with diffuse malignant peritoneal mesothelioma — G.H. Eltabbakh, M.S. Piver, et al. (1999)
• Conversion to Complete Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Malignant Peritoneal Mesothelioma After Bidirectional Chemotherapy — F. Le Roy, M. Gelli, et al. (2017)
• Intraperitoneal therapy for peritoneal tumors: biophysics and clinical evidence — W.P. Ceelen, M.F. Flessner (2010)
• Neoadjuvant Pressurized Intraperitoneal Aerosol Chemotherapy for Conversion to Cytoreductive Surgery in Unresectable Malignant Peritoneal Mesothelioma: A Report of 2 Cases — A. Urbano-Ruiz, B. Latronico Palma, et al. (2026)
• Well-differentiated papillary mesothelioma of the peritoneum: a pathological analysis and review of the literature — A.V. Hoekstra, M.W. Riben, et al. (2005)

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