Hematological, histomorphological, and immunohistochemical diagnosis of bilateral testicular Sertoli cell tumor in a Mongrel dog: a case history

Although testicular tumors are the most common genital system tumors in dogs, Sertoli cells tumors (SCT) are the least occurring of them all to warrant their continuous evaluations. More so, SCTs may present some microscopic diagnostic difficulties requiring the use of other diagnostic tools. The present study focused on hematological, histomorphological and immunohistochemical evaluation of bilateral testicular growths in a Mongrel dog. All vital parameters were within optimum ranges and all investigations were according to standard procedures. The disease condition was characterized by lymphocytosis and thrombocytopenia with the rare bilateral grey to yellowish multilobulated testicular growths composed of diffuse haphazardly arranged uniform small round cells with scanty cytoplasm and hyperchromatic round to oval nuclei in a nest-like formation separated by little intercellular fibrillar septa, which reacted positively to only vimentin and NSE and also α-SMA (fibrillar septa only) but negatively to CD3, CD20, CD99, CK A1/A3, CD117, LCA, desmin, S-100, HMB45, β-HCG, E-cadherin, synaptophysin, and NFP antibodies, respectively. A diagnosis of bilateral canine SCT with tendency towards metastasis became imperative based on the study findings. Surgical excision of the mass was performed and managed. The used large battery of immunohistochemical antibodies highlighted their diagnostic potentials in aiding histopathological diagnosis of canine SCTs in veterinary practice. The findings further highlighted the need for the continuous monitoring of sexually active dogs with descended testis for cases of SCTs.