Testicular tumors are, after skin tumors, the most common neoplasms in male dogs. Among all animals, these tumors occur most frequently within dogs. The etiology remains unclear, although the ectopic (non-scrotal) positioning of the testicles has an influence on tumor development. The most common types of testicular tumors include seminomas, Sertoli cell tumors, and interstitial (Leydig) cell tumors. The aim of this study was a retrospective evaluation of preserved material. A total of 326 cases of testicular tumors in dogs, diagnosed between 2017 and 2024, were analyzed. A histological analysis of multiple unilateral testicular tumors was conducted, and the frequency of occurrence was determined. 27 instances (8.28%) of multiple tumors within the same testicle were identified. The most recurrent combination was seminoma and interstitial cell tumors-12 cases (44.44%), followed by Sertoli cell and Leydig cell tumors-6 cases (22.22%), and seminoma and Sertoli cell tumors-6 cases (22.22%). In three cases, the presence of three tumors within a single testicle was observed (11.11%). In one case, double tumors were found within both testicles. It was observed that malignant features, as in cases of single testicular tumors, are rare.
Keywords: Sertoli cell tumor; dog; interstitial cell tumor; multiple testicular tumors; seminoma; unilateral.