Chylopericardium in a Dog with Concurrent Chylothorax, Mesothelioma, and Bilateral Brachiocephalic Vein Thrombosis: A Case Report

Our plain-English summary of Chylopericardium in a Dog with Concurrent Chylothorax, Mesothelioma, and Bilateral Brachiocephalic Vein Thrombosis: A Case Report, by T. Yoshida, K. Terai, A. Takeuchi, et al (Veterinary Sciences, 2026).

The study

• Authors: T. Yoshida, K. Terai, A. Takeuchi, A. Hatanaka, R. Hayashi, Y. Takahashi, D. Ito, H.M. El-Husseiny, T. Tanaka, R. Tanaka
• Journal: Veterinary Sciences
• Published: 2026;13(7)
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Chylopericardium is an extremely rare disorder in dogs, and its underlying mechanisms and optimal management strategies remain poorly defined. This report describes a dog with chylopericardium complicated by concurrent chylothorax, bilateral brachiocephalic vein thrombosis, and mesothelioma. A 6-year-old neutered male Shiba Inu presented with respiratory distress and was diagnosed with chylothorax and chylopericardium based on fluid analysis. Computed tomography revealed multiple thoracic ducts and bilateral brachiocephalic vein thrombosis but no definitive site of lymphatic leakage. Surgical management included thoracic duct ligation, subtotal pericardiectomy, and cisterna chyli ablation. Histopathological examination of resected pericardial and mediastinal tissues confirmed mesothelioma. Postoperatively, pleural effusion initially decreased but subsequently recurred, and intrathoracic chemotherapy with carboplatin was administered, resulting in long-term control of chylous effusion. Antithrombotic therapy was also initiated for venous thrombosis. The dog remained free of chylous fluid accumulation until death from an unrelated disease. This case highlights the complex interactions among lymphatic, vascular, and neoplastic disorders and suggests that a comprehensive, multimodal diagnostic and therapeutic approach may be effective for managing complicated cases of chylopericardium in dogs.

In plain English

This was a case report about one dog, a 6-year-old neutered male Shiba Inu, seen for breathing difficulty at a veterinary teaching hospital in Tokyo, Japan. Fluid tests showed chyle, a milky lymph fluid, both in the chest (chylothorax) and in the sac around the heart (chylopericardium). Scans showed three thoracic ducts and blood clots in both brachiocephalic veins, but no leak site. Surgeons tied off the thoracic ducts, removed most of the heart sac, and disrupted the cisterna chyli. Tissue from the heart sac and mediastinum showed findings the authors considered most consistent with mesothelioma. Chylous fluid appeared to return by day 27. Carboplatin was given into the chest on days 27 and 41, after which no pleural effusion was detected. The clots had fully resolved on a scan four months after the anti-clotting drug clopidogrel was started. The dog died on day 267 from a ruptured liver hemangiosarcoma. The authors concluded that mesothelioma may have contributed to the chylopericardium, but they could not establish cause. Immunohistochemistry was not done, and one case cannot be generalized. The article does not mention asbestos.

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 dog)
• Who was studied: One 6-year-old, 12.06-kg, neutered male Shiba Inu dog with respiratory distress, referred to the Veterinary Teaching Hospital, Tokyo University of Agriculture and Technology, Japan
• Exposure: The article reports no asbestos or other environmental exposure and does not discuss what caused the mesothelioma; the treatments described were surgery, clopidogrel, and intrathoracic carboplatin
• Main results:
  • The fluid around the heart had a triglyceride level above 500 mg/dL, consistent with chylopericardium
  • CT lymphangiography found no leak site and no clear connection between the thoracic duct and the lymph vessels of the heart sac
  • CT angiography showed blood clots in both brachiocephalic veins
  • Tissue removed from the heart sac (pericardium) and mediastinum showed findings most consistent with mesothelioma
  • On day 27 after admission, the triglyceride level in the chest fluid was 182 mg/dL, higher than the serum level of 121 mg/dL, suggesting that chylous effusion had returned after surgery
  • Carboplatin (100 mg/m2) was given into the chest on days 27 and 41, after which no pleural effusion was detected
  • Four months after clopidogrel was started, CT angiography showed the brachiocephalic vein clots had fully resolved
  • The dog died on day 267 from a ruptured liver (hepatic) hemangiosarcoma, with no return of pleural effusion before death
• The authors' conclusion: The authors concluded that a direct causal link could not be established, but that the clinical course suggests mesothelioma may have contributed to the chylopericardium by impairing lymphatic drainage. In their view, the combined treatment controlled the chylous effusion long-term in this individual dog.
• Limitations the authors state:
  • Immunohistochemistry was not performed, so the authors could not completely rule out reactive mesothelial hyperplasia (a non-cancerous condition) instead of mesothelioma
  • Coagulation testing was not done, so the role of cancer-related clotting in the vein thrombosis could not be fully evaluated
  • Causal links among mesothelioma, chylothorax, vein thrombosis, and chylopericardium could not be definitively established
  • Direct evidence that the tumor had invaded the lymph vessels was not found
  • As a single case, the findings cannot be generalized to other dogs

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Bilateral, Pericardiectomy, Pericardial, Pleural Effusion, Intrathoracic, Chemotherapy, Carboplatin.

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