Department of Pathology, Division of Pathomorphology and Veterinary Forensics, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, C.K. Norwida 31, Wroclaw, 50-375, Poland.
Department of Veterinary Medicine and Animal Science, University of Milan, via dell'Università 6, Lodi, 26900, Italy.
BMC Vet Res. 2023 Jul 31;19(1):101. doi: 10.1186/s12917-023-03658-5.
Testicular tumours are common in dogs and, among them, interstitial cell tumours, seminomas and sustentacular cell tumours are the most reported. Mesenchymal testicular tumours are rarely reported in humans as in veterinary medicine where only three cases of sarcomas (leiomyomas and leomyosarcomas) have been described in two stallions and in a ram.
The present cases regarded a 12-year-old mixed-breed dog and a 10-year-old American Staffordshire Terrier that underwent bilateral orchiectomy. Formalin fixed testes were referred for histopathological diagnosis. At gross examination, in one of the testes of both dogs, a white, firm and variably cystic testicular mass, effacing and replacing the testicular parenchyma was detected. Samples were collected from both neoplastic and contralateral testes, routinely processed for histology and serial sections were also examined immunohistochemically with primary antibodies against cytokeratins, vimentin, Von Willebrand factor, inhibin-α, α-smooth muscle actin, smooth muscle myosin and desmin. Histopathological features as well as the immunohistochemical results, positive for vimentin, actin, myosin and desmin, confirmed the mesenchymal origin and the myoid phenotype of both testicular tumours supporting the diagnoses of leiomyosarcoma.
To the authors knowledge these are the first cases of primary testicular sarcoma reported in the canine species. However, even rare, these tumours deserve to be considered in routine diagnosis when a testicular spindle cell tumour is observed. The immunohistochemical panel applied was useful to distinguish the present tumours from undifferentiated Sertoli cell tumours confirming the diagnosis of leiomyosarcoma.
睾丸肿瘤在犬中较为常见，其中间质细胞瘤、精原细胞瘤和支持细胞瘤最为常见。间质性睾丸肿瘤在人类中很少见，但在兽医医学中，仅在 2 匹种马和 1 只公羊中描述过 3 例肉瘤（平滑肌瘤和平滑肌肉瘤）。
本病例涉及一只 12 岁的混种犬和一只 10 岁的美国斯塔福德郡梗，它们均接受了双侧睾丸切除术。福尔马林固定的睾丸被送检进行组织病理学诊断。在大体检查中，这两只犬的一只睾丸中发现了一个白色、坚硬且具有不同程度囊性的睾丸肿块，使睾丸实质消失并被取代。从两个肿瘤和对侧睾丸中采集了样本，常规进行组织学处理，并对连续切片进行了细胞角蛋白、波形蛋白、血管性血友病因子、抑制素-α、α-平滑肌肌动蛋白、平滑肌肌球蛋白和结蛋白的免疫组织化学染色。组织病理学特征以及免疫组织化学结果（波形蛋白、肌动蛋白、肌球蛋白和结蛋白阳性）证实了这两种睾丸肿瘤的间充质起源和肌源性表型，支持平滑肌肉肉瘤的诊断。
据作者所知，这些是犬种中首例原发性睾丸肉瘤病例。然而，即使罕见，当观察到睾丸梭形细胞肿瘤时，这些肿瘤也应在常规诊断中考虑。应用的免疫组织化学组合有助于将本肿瘤与未分化的支持细胞瘤区分开来，从而确认平滑肌肉肉瘤的诊断。
