Case Report: Clinical course and extended survival in a canine patient with pericardial mesothelioma managed without chemotherapeutic intervention

Our plain-English summary of Case Report: Clinical course and extended survival in a canine patient with pericardial mesothelioma managed without chemotherapeutic intervention, by S.G. Park, S. Lim, J. Moon, et al (Frontiers in Veterinary Science, 2026).

The study

• Authors: S.G. Park, S. Lim, J. Moon, O. I-Se, T. Chung, D. Kim
• Journal: Frontiers in Veterinary Science
• Published: 2026;13:1808005
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Pericardial mesothelioma is a rare and aggressive neoplasm in dogs, typically associated with a poor prognosis and limited treatment options. While chemotherapy is commonly employed, there is limited literature describing successful management without chemotherapeutic intervention. This case report describes a 7-year-old spayed female Pomeranian presenting with acute respiratory distress caused by pericardial effusion. Initial management included pericardiocentesis and medications, but recurrence of the effusion necessitated surgical intervention. Subtotal pericardiectomy was performed, and malignant pericardial mesothelioma was confirmed histopathologically. A thoracic port was implanted postoperatively for ongoing effusion management. The patient remained clinically stable and maintained a good quality of life for 628 days without chemotherapy, supported by regular monitoring and comprehensive symptomatic care. This case highlights that prolonged survival may be achieved through aggressive effusion control and surgical intervention in dogs with pericardial mesothelioma when systemic chemotherapy is not feasible.

Copyright © 2026 Park, Lim, Moon, I-se, Chung and Kim.

In plain English

This case report described one dog, a 7-year-old spayed female Pomeranian, with malignant pericardial mesothelioma, a cancer of the sac around the heart. The dog lived indoors and had no known exposure to toxic substances, including smoke and asbestos. It first came in with breathing difficulty from fluid around the heart and in the chest, and the fluid was drained. The dog stayed stable for about 9 months. After that, fluid around the heart kept returning and had to be drained more and more often. A CT scan raised suspicion of mesothelioma. Surgeons removed part of the sac around the heart, and tissue examination confirmed the cancer. The owner declined chemotherapy because of cost and possible side effects. A chest drainage port was placed, and chest fluid was drained repeatedly from Day 540. The dog died of respiratory arrest on Day 628, about 21 months after first presentation. The authors concluded that survival may be prolonged without chemotherapy. They noted that one case cannot compare treatments and that immunohistochemistry, a special tissue staining test, was not done.

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 a single client-owned dog
• Who was studied: One 7-year-old spayed female Pomeranian dog weighing 4.58 kg at first presentation
• Exposure: No known asbestos exposure was reported. The dog lived indoors with no known exposure to toxic substances including smoke and asbestos. The treatment studied was management without chemotherapy: fluid drainage, subtotal pericardiectomy, a thoracic port and supportive drugs. The owner declined chemotherapy because of cost and possible side effects.
• Main results:
  • At first presentation (Day 0), drainage removed 50 mL of fluid from around the heart and 200 mL of fluid from the chest.
  • The dog remained stable without notable clinical signs for about 9 months. It was then hospitalized on Days 275 to 276 when breathing difficulty returned.
  • Cytology (cell examination) of the fluid around the heart on Day 276 did not show definitive cancer criteria.
  • Between Days 276 and 520, drainage of fluid from around the heart was needed progressively more often. Volumes ranged from 67 mL to 240 mL.
  • CT findings were considered consistent with a diffuse infiltrative cancer process, raising suspicion for mesothelioma.
  • Tissue examination of the surgically removed pericardium showed cancer cells invading the underlying connective tissue. This confirmed malignant pericardial mesothelioma.
  • After surgery, fluid in the chest returned progressively from Day 540 and was drained regularly through the implanted thoracic port.
  • The authors observed no major adverse events related to the procedures or drugs during follow-up.
  • Body weight rose from 4.58 kg to 6.02 kg over the clinical course.
  • The dog died of respiratory arrest on Day 628, an overall survival of about 21 months after the first presentation with fluid around the heart.
• The authors' conclusion: The authors concluded that survival may be prolonged without chemotherapy in dogs with pericardial mesothelioma. They said larger case series are needed to validate this observation.
• Limitations the authors state:
  • The report describes a single case.
  • Because chemotherapy was not given, the case cannot be used to compare chemotherapy with supportive management.
  • Immunohistochemical analysis was not performed, because of resource constraints.
  • Formal body condition scoring and dietary assessments were not done, which limits conclusions drawn from the weight trend.
  • The authors' explanation for why fluid shifted into the chest after surgery is speculative.
  • The authors' reason for giving tranexamic acid (local tumor-related clot breakdown) was not directly tested and remains inferential.

Topics

Medical terms in this study, explained in our Lexicon: Pericardial Mesothelioma, Neoplasm, Prognosis, Chemotherapy, Pericardial Effusion, Pericardiocentesis, Pericardiectomy, Quality of Life.

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