There are few pathological and immunohistochemical descriptions of thyroid neoplasms in cats. We investigated neoplasms of the thyroid in 31 cats (average age 15.6 years) in Southern Brazil. Most (96.8%) of these cases were classified as follicular adenomas and were predominantly unilateral and multinodular. Histologically, macrofollicular adenomas were the most common type observed. Carcinomas represented 3.2% of the investigated tumours. By immunohistochemical labelling, thyroglobulin was expressed more commonly than paired box gene 8 or thyroid transcription factor 1 in the follicular adenomas. One carcinoma was immunopositive for thyroglobulin, pancytokeratin, chromogranin A and synaptophysin, suggestive of a calcitonin-negative neuroendocrine carcinoma.

关于猫甲状腺肿瘤的病理学和免疫组织化学描述很少。我们调查了巴西南部 31 只猫（平均年龄 15.6 岁）的甲状腺肿瘤。这些病例中的大多数 (96.8%) 被归类为滤泡性腺瘤，主要是单侧和多结节。组织学上，大滤泡腺瘤是最常见的类型。癌占所研究肿瘤的 3.2%。通过免疫组织化学标记，甲状腺球蛋白在滤泡腺瘤中的表达比配对盒基因 8 或甲状腺转录因子 1 更常见。一种癌对甲状腺球蛋白、全细胞角蛋白、嗜铬粒蛋白 A 和突触素呈免疫阳性，提示降钙素阴性神经内分泌癌。