Canine thymic epithelial tumours (TET) are uncommon and little is known about their behaviour. Previous attempts at histologic classification have varied, and as such reliable prognostic information is unavailable. The aim of this retrospective multi-institutional study was to evaluate cases of canine TETs, irrespective of subtype, in order to identify useful histopathologic and clinicopathologic prognostic factors. Cases were included if the tumour arose from the cranial mediastinum and a diagnosis of TET was made on the basis of histopathology. Fifty-one dogs were included. In addition to clinicopathologic data, histology samples were reviewed for the following features: mitotic count, percentage of necrosis, presence of Hassall's corpuscles, lymphocytic infiltrate, cellular pleomorphism and vascular or capsular invasion. The median survival time for all dogs was 449 days. The 1- and 2-year survival rate was 52.6% and 26.3% respectively. On multivariable analysis surgical excision of the thymic tumour was associated with significantly prolonged survival; the presence of metastasis, myasthenia gravis and moderate or marked cellular pleomorphism were associated with significantly reduced survival. Additional studies are needed to further evaluate prognostic factors to aid treatment recommendations.

中文翻译：

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51 只狗的胸腺上皮肿瘤：组织病理学和临床病理学发现

犬胸腺上皮肿瘤 (TET) 并不常见，对其行为知之甚少。以前对组织学分类的尝试各不相同，因此无法获得可靠的预后信息。这项回顾性多机构研究的目的是评估犬 TET 病例，无论其亚型如何，以确定有用的组织病理学和临床病理学预后因素。如果肿瘤起源于颅纵隔并且根据组织病理学诊断为 TET，则纳入病例。包括 51 只狗。除了临床病理学数据外，还审查了组织学样本的以下特征：有丝分裂计数、坏死百分比、Hassall 小体的存在、淋巴细胞浸润、细胞多形性和血管或包膜侵犯。所有狗的中位生存时间为 449 天。1年和2年生存率分别为52.6%和26.3%。在多变量分析中，手术切除胸腺肿瘤与显着延长生存期相关；转移、重症肌无力和中度或显着细胞多形性的存在与生存率显着降低有关。需要更多的研究来进一步评估预后因素以帮助提出治疗建议。