A 3-year-old, 3.5-kg, neutered male, domestic shorthair cat presented with progressive lethargy, anorexia, coughing, and acute respiratory distress of two-week duration. Auscultation detected diffuse pulmonary crackles. Lung sounds were absent over the left cranial thorax. Sinus tachycardia was recorded. Thoracic radiographs revealed cardiac silhouette enlargement, dorsal displacement of the carina, and uniform, soft tissue opacity in the left cranial hemithorax. Transthoracic two-dimensional echocardiography revealed a large mass within and external to the pericardial space, effacing the pericardium, and compressing basal cardiac structures. The point-of-care feline immunodeficiency virus and feline leukemia virus test was negative. Euthanasia was elected, and permission for necropsy granted. Gross postmortem evaluation revealed a prominent mediastinal mass that effaced the left cranial lung lobe and invaded the heart base and pericardium. The mass was confirmed as B-cell lymphoma by histopathology and immunohistochemistry.

一只 3 岁、3.5 公斤、已绝育的雄性家养短毛猫出现进行性嗜睡、厌食、咳嗽和持续两周的急性呼吸窘迫。听诊发现肺部弥漫性湿啰音。左颅胸肺音未见。记录窦性心动过速。胸片显示心脏轮廓扩大，隆突背侧移位，左颅侧半胸均匀的软组织混浊。经胸二维超声心动图显示心包间隙内外有一个大肿块，覆盖心包并压迫基底心脏结构。床旁猫免疫缺陷病毒和猫白血病病毒检测呈阴性。安乐死被选举出来，并获得了尸检许可。尸检大体评估显示显着的纵隔肿块消失了左颅肺叶并侵入了心脏基底和心包。该肿块经组织病理学和免疫组织化学证实为 B 细胞淋巴瘤。