[Metastatic seminoma in the orbital region in a dog - case report]

ABSTRACT Seminoma is a testicular neoformation originating from germ cells, commonly occurring in dogs. With higher prevalence in senile animals, the biological behavior of canine seminomas generally benign. This case reports seminoma with mestastasis in the orbital region in a 14-year-old dog. The animal was treated with a complaint of increased volume in the left orbit, and later a nodule in the testicle was discovered. Fine-needle aspiration of the orbit mass initially indicated a high-grade lymphoma. The definitive diagnosis of diffused seminoma was established by histopathological examination, resulting in poorly differentiated malignant neoplasia. Finally, the diagnosis was confirmed through immunohistochemistry, being the result compatible with diffused seminoma. Metastatic seminomas reported in dogs are quite uncommon. In this work we report a case of diffused anaplastic seminoma in dogs, where the main focus of metastasis was observed in the orbital region, and we also describe and discuss the difficulties encountered in the diagnostic.

【摘要】精原细胞瘤（Seminoma）是一种起源于生殖细胞（germ cells）的睾丸新生物，常见于犬类。该病症在老年动物中患病率更高，犬类精原细胞瘤的生物学行为通常呈良性。本文报告一例发生于14岁犬眼眶区域的转移性精原细胞瘤病例。该犬因左侧眼眶体积增大前来就诊，后续检查发现其睾丸存在结节。最初对眼眶肿物实施细针抽吸活检（fine-needle aspiration），结果提示为高级别淋巴瘤。最终通过组织病理学检查（histopathological examination）确诊为弥漫性精原细胞瘤，属于低分化恶性肿瘤；随后借助免疫组织化学（immunohistochemistry）验证了诊断结果，检测结果与弥漫性精原细胞瘤相符。犬类转移性精原细胞瘤较为罕见，本文报告一例以眼眶区域为主要转移灶的犬弥漫性间变性精原细胞瘤病例，并对诊断过程中遇到的难点进行了描述与讨论。