Rare Metastatic Mesothelioma Occupying Intra-Atrial Cavity, Released by an Emergency Surgery: A Case Report and Literature Review

Our plain-English summary of Rare Metastatic Mesothelioma Occupying Intra-Atrial Cavity, Released by an Emergency Surgery: A Case Report and Literature Review, by T. Takano, S. Sato, I. Ito, et al (Surgical Case Reports, 2025).

The study

• Authors: T. Takano, S. Sato, I. Ito, M. Yamamoto, K. Tsukioka, Y. Matsumura, T. Kono
• Journal: Surgical Case Reports
• Published: 2025;11(1)
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: Cardiac surgery for cardiovascular-associated mesothelioma has a poor prognosis. However, life-saving surgery is unavoidable to maintain circulation. This report describes a case in which metastatic intracardiac mesothelioma triggered sudden respiratory failure, which was reduced by surgical resection.

Case Presentation: An 81-year-old man with a history of asbestos exposure presented to our hospital with sudden onset of dyspnea. Prior to this event, the pleura was involved in an epithelial malignancy, which was immunohistochemically negatively stained with anti-D2-40, WT-1, or anti-calretinin antibodies, which are positive markers of mesothelioma. Transthoracic echocardiography revealed a fragile and mobile tumor occupying the right atrium, and the patient was admitted for surgical tumorectomy. The operation was performed urgently using a cardiopulmonary bypass via a full sternotomy. The pericardium is grossly intact and does not adhere to the heart. A 3 × 5 cm tumor was tightly attached to the right atrium and was large enough to fit into the tricuspid valve. Therefore, the entire margin of the tumor stem attachment was resected from the lateral wall of the right atrium. Although the resected tumor was not positive for any of the three histopathological markers of mesothelioma, CDKN2A co-deletion revealed by fluorescence in situ hybridization led to a diagnosis of malignant mesothelioma.

Conclusions: Surgical removal of intracardiac tumors that cause circulatory and respiratory instability is essential for the prevention of sudden death, regardless of prognostic determinants. This case demonstrates that mesotheliomas can metastasize to the endocardium. Even when nuclear atypia and negative results for immunohistochemical tests for the three mesothelioma markers suggest carcinoma, mesothelioma should still be considered and p16/CDKN2A co-deletion should be evaluated.

© 2025 The Author(s). Published by Japan Surgical Society.

In plain English

This case report, with a literature review, described an 81-year-old man in Japan with a history of asbestos exposure who came to the hospital with sudden shortness of breath. Ten months before surgery, a pleural biopsy had shown a cancer of unknown primary site, suspected to be lung adenocarcinoma or malignant mesothelioma. The biopsy did not stain for the mesothelioma markers WT-1, calretinin and D2-40, and the patient was treated with an immune checkpoint inhibitor, as for non-small cell lung cancer. A heart ultrasound now showed a fragile, mobile tumor in the right atrium. In emergency surgery the tumor, attached to the right atrial wall, was removed, and the pericardium looked intact. A genetic test (FISH) of the removed tumor showed loss of the CDKN2A/p16 gene. Together with the staining results, this led to a diagnosis of metastatic malignant mesothelioma. The patient left the hospital on postoperative day 54 and died of pneumonia two months after surgery. No autopsy was done. The authors concluded that this case shows mesotheliomas can metastasize to the endocardium, the inner lining of the heart.

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 with literature review
• Who was studied: One 81-year-old man with a history of asbestos exposure, treated at Nagano Red Cross Hospital, Japan; dates not given
• Exposure: A history of asbestos exposure; no fiber type, job, product or dose is given
• Main results:
  • Heart ultrasound showed a fragile, mobile tumor occupying the right atrium
  • At emergency surgery the pericardium was grossly intact and not adhering to the heart; the tumor was tightly attached to the right atrium and was removed
  • The mesothelial markers calretinin, D2-40 and WT-1 did not show the staining typical of mesothelioma, and the cancer markers CEA, TTF-1 and Napsin A were negative
  • FISH of the resected atrial tumor showed homozygous loss of CDKN2A/p16, suggestive of mesothelioma
  • The authors considered the atrial tumor a metastatic neoplasm
  • Cytology of the pericardial fluid showed malignant findings, but no gross pericardial tumor was seen
  • The patient was discharged on postoperative day 54 and died of pneumonia 2 months after surgery
• The authors' conclusion: The authors concluded that this case demonstrates that mesotheliomas can metastasize to the endocardium. They also concluded that surgical removal of intracardiac tumors causing circulatory and respiratory instability is essential to prevent sudden death.
• Limitations the authors state:
  • No autopsy or further pathology was performed, so no further data were obtained
  • Contrast-enhanced CT before surgery could not be done because of a contrast allergy

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Prognosis, Surgical Resection, Asbestos Exposure, Dyspnea, Pleura, Podoplanin (D2-40), Wilms Tumor 1 (WT-1).

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