A Case of Duodenal Metastasis From Malignant Pleural Mesothelioma Diagnosed by Gastrointestinal Endoscopy Following Progressive Anemia During Salvage Chemotherapy

Our plain-English summary of A Case of Duodenal Metastasis From Malignant Pleural Mesothelioma Diagnosed by Gastrointestinal Endoscopy Following Progressive Anemia During Salvage Chemotherapy, by N. Ichiyama, H. Yamane, T. Saitou, et al (Thoracic Cancer, 2025).

The study

• Authors: N. Ichiyama, H. Yamane, T. Saitou, M. Miura, A. Mimura, Y. Kosaka, T. Kawahara, Y. Nagasaki, N. Ochi, H. Nakanishi, H. Fujiwara, N. Takigawa
• Journal: Thoracic Cancer
• Published: 2025;16(11):e70098
• Type of article: Case report, Review
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant pleural mesothelioma (MPM) primarily progresses through direct invasion into the lung and pleura and is a refractory tumor in which asbestos exposure is a major underlying factor in most cases. Hematogenous metastasis of MPM is not uncommon in advanced stages, and reports suggest that metastatic sites may impact prognosis. Gastrointestinal metastases, ranging from the stomach to the colon, have been sporadically observed, but metastases to the small intestine and duodenum are exceedingly rare. Here, we report a case in which duodenal metastasis of MPM was endoscopically identified during the patient's lifetime while undergoing salvage chemotherapy following treatment with an immune checkpoint inhibitor and cytotoxic chemotherapy. Given the rarity and clinical significance of such cases, we present this report with a review of the relevant literature.

© 2025 The Author(s). Thoracic Cancer published by John Wiley & Sons Australia, Ltd.

In plain English

This was a case report with a short review of earlier published cases. It described a 68-year-old man in Japan with about 2 years of asbestos exposure in his 20s. The article did not name the fiber type. His pleural effusion was first managed as a benign asbestos pleural effusion, but a 2022 biopsy confirmed malignant pleural mesothelioma (biphasic type, Stage IB). The cancer came back in neck lymph nodes in October 2022, after chemotherapy and surgery, and later progressed despite immune checkpoint inhibitor therapy and chemotherapy. In October 2024, rapidly worsening anemia (hemoglobin falling from 9.6 to 7.2 g/dL) led to an endoscopy. It found a 10-mm lesion in the duodenum, which a biopsy showed was spread from the mesothelioma. The authors concluded that the anemia came from bleeding from this lesion. He died in early November 2024 of worsening respiratory failure. In a PubMed search, the authors found six earlier reports of small-intestine spread from pleural mesothelioma, none in the duodenum. They concluded that endoscopy to investigate anemia in advanced mesothelioma can occasionally find such spread.

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 brief literature review of earlier published cases
• Who was studied: One 68-year-old man treated at Kawasaki Medical School, Okayama, Japan. He first presented with pleural effusion in late November 2020 and died in early November 2024.
• Exposure: Approximately 2 years of asbestos exposure in his 20s. The fiber type and the job are not stated.
• Main results:
  • The effusion was initially managed as a benign asbestos pleural effusion. A biopsy in February 2022 confirmed malignant pleural mesothelioma of the biphasic type with heterologous elements, clinical Stage IB (T2N0M0).
  • The patient had three courses of cisplatin and pemetrexed and then pleurectomy and decortication in June 2022. The tumor recurred in October 2022 with metastasis to the left cervical lymph nodes. It then progressed despite ipilimumab plus nivolumab and cytotoxic chemotherapy.
  • In early October 2024, the patient's hemoglobin fell rapidly from 9.6 g/dL to 7.2 g/dL. Endoscopy (EGD) found a 10-mm flat, elevated lesion in the descending part of the duodenum.
  • A biopsy of the duodenal lesion confirmed metastasis from the pleural mesothelioma.
  • The patient's anemia was microcytic and hypochromic, and the fecal occult blood test was positive. The lesion bled with minimal contact, and a colonoscopy found no other obvious bleeding source. The authors concluded that the anemia was due to bleeding from the duodenal lesion.
  • In palliative care, the patient needed blood transfusions every 1 to 2 weeks. He died in early November 2024 from worsening respiratory failure.
  • A PubMed search yielded 19 articles, of which six reported small-intestine metastasis from pleural mesothelioma. All of those patients were male, with a mean age of 61.6 years, and the metastases were mainly in the jejunum.
  • Within the authors' search, no earlier case of duodenal metastasis was found apart from the present case.
  • Of the six earlier cases, five required surgery because of acute abdomen or intussusception.
• The authors' conclusion: The authors concluded that duodenal metastasis is an extremely rare site of spread for pleural mesothelioma. They suggested that endoscopic evaluation of anemia in patients with advanced mesothelioma can occasionally identify metastatic lesions.

Topics

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

Medical terms in this study, explained in our Lexicon: Metastasis, Pleural Mesothelioma, Endoscopy, Chemotherapy, Pleura, Asbestos Exposure, Prognosis, checkpoint inhibitors.

Related studies

• Duodenal metastasis of malignant pleural mesothelioma — H.C. Chen, K.B. Tsai, et al. (2008)
• Successful salvage chemotherapy with gemcitabine and vinorelbine in a malignant pleural mesothelioma patient previously treated with pemetrexed — T. Agatsuma, T. Koizumi, et al. (2010)
• Salvage therapy with topical antifungal for Aspergillus fumigatus empyema complicating extrapleural pneumonectomy — M. Purohit, A. Guleri, et al. (2012)
• Apatinib for salvage treatment of advanced malignant pleural mesothelioma: A case report — Z. Du, Y. Yu, et al. (2018)
• Tremelimumab for patients with chemotherapy-resistant advanced malignant mesothelioma: an open-label, single-arm, phase 2 trial — L. Calabrò, A. Morra, et al. (2013)
• Phase 2 study of sorafenib in malignant mesothelioma previously treated with platinum-containing chemotherapy — S. Papa, S. Popat, et al. (2013)

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