An 8-year-old neutered male French Bulldog was presented with a 2-day history of intermittent vomiting, reduced appetite and recent rapid development of multiple cutaneous masses over the head and neck regions. On presentation, the patient had a moderate volume of pericardial and bilateral pleural effusion. Echocardiography demonstrated irregular, heterogeneous thickening of the walls of the right ventricle and right atrium, consistent with infiltrative intramyocardial disease. Cytological examination of fine needle aspirates from one of the cutaneous masses confirmed a mast cell tumour. Pericardial fluid analysis revealed a haemorrhagic neoplastic effusion due to mast cell neoplasia. Histopathological and immunohistochemical examination of tissues obtained post mortem confirmed a high-grade cutaneous mast cell tumour with metastasis to the heart, pericardium, mediastinum and spleen. No metastatic disease was present in the submandibular lymph nodes or liver. Immunohistochemistry demonstrated KIT staining pattern 2. There was strong nuclear Ki67 labelling in an average of 65.0 cells per grid and an average of three positive AgNORs per nucleus in neoplastic cells. Polymerase chain reaction for the activating duplication mutation in exons 8 and 11 of c-Kit were negative. To the authors’ knowledge, this is the first report of a canine cutaneous mast cell tumour associated with neoplastic pericardial effusion and widespread intrathoracic metastasis.

一只 8 岁的绝育雄性法国斗牛犬出现 2 天的间歇性呕吐病史，食欲下降，近期头颈部多处皮肤肿块快速发展。就诊时，患者有中等量的心包和双侧胸腔积液。超声心动图显示右心室和右心房壁不规则、不均匀增厚，与浸润性心肌内疾病一致。对来自其中一个皮肤肿块的细针抽吸物的细胞学检查证实了肥大细胞肿瘤。心包液分析显示由于肥大细胞瘤形成的出血性肿瘤积液。对死后获得的组织进行组织病理学和免疫组织化学检查证实为高级别皮肤肥大细胞肿瘤，转移至心脏、心包、纵隔和脾脏。下颌下淋巴结或肝脏中没有转移性疾病。免疫组织化学显示 KIT 染色模式 2。在每个网格平均 65.0 个细胞中存在强核 Ki67 标记，在肿瘤细胞中每个细胞核中平均有 3 个阳性 AgNOR。c-Kit 外显子 8 和 11 中激活重复突变的聚合酶链反应为阴性。据作者所知，这是与肿瘤性心包积液和广泛的胸腔内转移相关的犬皮肤肥大细胞肿瘤的第一份报告。