Cardiac tamponade in a cat with pericardial mesothelioma

Our plain-English summary of Cardiac tamponade in a cat with pericardial mesothelioma, by F. Spina, M. Orlandi, R. Preziosi, et al (Veterinary Research Communications, 2026).

The study

• Authors: F. Spina, M. Orlandi, R. Preziosi, G. Giglia, M. Sforna, F. Birettoni
• Journal: Veterinary Research Communications
• Published: 2026;50(3)
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Pericardial effusion is uncommon in cats and most often secondary to congestive heart failure, feline infectious peritonitis or neoplasia. Primary cardiac tumors are rare in companion animals, with their occurrence being particularly uncommon in cats and among these, mesothelioma is exceptionally rare. Its antemortem diagnosis presents a considerable challenge due to the often-mild nature of intrapericardial fluid accumulation and the difficulty in cytologically differentiating neoplastic cells from reactive mesothelial cells. A 12-year-old Domestic Shorthair cat was presented for dyspnea and weakness. Ultrasound examination revealed concurrent pleural, peritoneal and pericardial effusion. Pericardial effusion appeared densely particulate with multiple small nodules on the epicardial surface. Pericardiocentesis acutely resolved the cardiac tamponade, but recurrence prompted subtotal pericardiectomy. Histopathology of surgical biopsies suggested pericardial mesothelioma. Despite surgery, the cat’s clinical condition deteriorated, leading to euthanasia one month later. Autopsy, histopathology and immunohistochemistry (positive for cytokeratin AE1/AE3, vimentin, calretinin and HBME-1) confirmed pericardial mesothelioma with pleural dissemination. This report describes the clinical, diagnostic, and pathological features of a rare case of feline pericardial mesothelioma and highlights the diagnostic value of a multimodal approach.

In plain English

This case report described a 12-year-old neutered male Domestic Shorthair cat referred for sudden weakness, loss of appetite and difficulty breathing. Heart ultrasound showed dense fluid in the sac around the heart (the pericardium) pressing on the right side of the heart, a condition called cardiac tamponade. It also showed small nodules on the heart surface, and fluid in the chest and abdomen. Draining the fluid relieved the tamponade. Cell testing of the fluid showed reactive mesothelial cells without atypia. Fluid around the heart came back and was drained again at 10 and 20 days, so part of the pericardium was surgically removed. Biopsies suggested pericardial mesothelioma. The cat declined and was euthanized one month later. Autopsy found nodules on the pericardium, the heart surface and the chest lining. Tissue examination and staining tests confirmed pericardial mesothelioma of the epithelioid type, with spread to the chest lining. The authors concluded that pericardial mesothelioma should be considered in cats with massive pericardial effusion and tamponade. The article did not mention asbestos or any other exposure.

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 cat)
• Who was studied: One 12-year-old neutered male Domestic Shorthair cat with acute weakness, anorexia and dyspnea. The authors are based in Italy, and the autopsy was done at the University of Perugia. No dates of the case are given.
• Exposure: Not reported. The article does not discuss asbestos or any other environmental or occupational exposure. It notes only that the cat had been boarded in a cattery two weeks before presentation.
• Main results:
  • Echocardiography showed severe, densely particulate fluid around the heart with diastolic collapse of the right atrium and ventricle, confirming cardiac tamponade.
  • At first drainage, 130 mL of pleural fluid, 100 mL of pericardial fluid and 120 mL of peritoneal fluid were removed.
  • The pericardial fluid was a high protein modified transudate (protein 4.1 g/dL), and the pleural fluid was chylous. Cytology of the pericardial and pleural fluid showed reactive mesothelial cells without atypia.
  • Pericardial effusion recurred and was drained again at 10 and 20 days after first presentation, leading to subtotal pericardiectomy.
  • The authors considered the pleural and peritoneal effusions to be secondary to the cardiac tamponade, because they did not come back after the tamponade was relieved.
  • In the surgical biopsy, the mitotic count was 5 per 2.37 mm², with 2 atypical mitotic figures in 2.37 mm².
  • The cat was euthanized one month after surgery, after its general condition declined.
  • At autopsy, the pericardium was thickened and the epicardium had nodules and plaques. Firm yellow nodules were also scattered on the parietal pleura.
  • Autopsy, histopathology and immunohistochemistry confirmed pericardial mesothelioma with pleural dissemination. The authors described this as a definitive postmortem diagnosis.
  • An epithelioid mesothelioma with a tubulopapillary pattern was diagnosed.
  • On immunohistochemistry, cytokeratin (AE1/AE3) and HBME-1 were each expressed in 90% of neoplastic cells.
  • On immunohistochemistry, calretinin was expressed in 85% of neoplastic cells and vimentin in 60%.
• The authors' conclusion: The authors concluded that primary pericardial mesothelioma should be considered in cats with massive pericardial effusion and cardiac tamponade, particularly when echocardiography shows densely particulate fluid and an irregular heart surface. In this case, pericardiectomy gave temporary palliation and provided biopsies for the diagnosis.

Topics

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

Medical terms in this study, explained in our Lexicon: Cardiac Tamponade, Pericardial Mesothelioma, Pericardial Effusion, Mesothelioma, Reactive Mesothelial Hyperplasia, Dyspnea, Ultrasound, Pericardiocentesis.

Related studies

• Sarcomatoid Type Primary Pericardial Mesothelioma with a Long-term Survival after the Onset of Cardiac Tamponade — C. Saisho, H. Ishii, et al. (2016)
• Cardiac tamponade as the initial manifestation of primary pericardial mesothelioma — M. Stein, A. Neuman, et al. (1995)
• Unexpected malignant pericardial mesothelioma presenting as pericardial constriction — M. Oc, B. Oc, et al. (2012)
• An unusual case of cardiac tamponade following electrical cardioversion — G.A. Jessurun, H.J. Crijns, et al. (1996)
• Successful palliation for an aged patient with primary pericardial mesothelioma — R. Isoda, H. Yamane, et al. (2015)
• Post-irradiation pericardial malignant mesothelioma: an autopsy case and review of the literature — M. Bendek, M. Ferenc, et al. (2010)

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