Tomohiro Yoshida

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.

Tracheal stent fracture is a major complication of endoluminal tracheal stent (ELS) for canine tracheal collapse, and optimal management strategies remain unclear. A 4-year-old Yorkshire Terrier presented with respiratory distress caused by complete ELS fracture. Imaging and bronchoscopy revealed intraluminal protrusion of fractured stent segments, ventral tracheal cartilage invagination, and marked luminal deformation. A parallel loop line prosthesis (PLLP) was selected as an external tracheal support. Its continuous band-like structure allowed broad and uniform reinforcement of the tracheal wall and redistribution of mechanical stress. PLLP placement successfully restored a near-normal tracheal contour and stabilized the fractured stent without introducing additional intraluminal material. Postoperative bronchoscopy confirmed improved tracheal patency, and no further deformation or stent damage was observed despite several months of altered airway dynamics associated with laryngeal paralysis. This case suggests that PLLP may represent a valid surgical option for managing tracheal stent fracture in dogs.

In human medicine, the 2025 International Society for the Study of Vascular Anomalies (ISSVA) classification distinguishes localized lymphatic malformations from systemic disorders referred to as complex lymphatic anomalies (CLAs), including generalized lymphatic anomaly (GLA) and central conducting lymphatic anomaly (CCLA). GLA is characterized by multifocal proliferation of dilated lymphatic channels infiltrating soft tissues and visceral organs, whereas CCLA involves structural or functional abnormalities of the central lymphatic pathways such as the thoracic duct commonly resulting in chylous effusion. Reports of systemic lymphatic disease in veterinary species are exceedingly rare. A five-month-old intact male domestic shorthair cat presented with progressive dyspnea and was diagnosed with chylothorax and chylous ascites. Computed tomography (CT) revealed contrast leakage from both the thoracic duct and aortic hiatus, along with diffuse subcutaneous edema, indicating a systemic lymphatic disorder. Histopathology demonstrated proliferative lymphatic channels within the subcutaneous tissues, consistent with GLA, while imaging findings suggested concurrent CCLA, supporting classification as an overlapping CLA phenotype. Despite medical and surgical interventions, the cat developed progressive edema and recurrent pleural effusion and ultimately died. This case demonstrates that cats can develop systemic lymphatic disorders analogous to human CLAs and highlights the diagnostic value of CT lymphangiography. Furthermore, it underscores the utility of applying the ISSVA classification to enhance comparative understanding of lymphatic diseases in veterinary medicine.