Concurrent Leydig and Sertoli Cell Tumors Associated with Testicular Mycosis in a Dog: A Case Report and Literature Review.

Mycosis is caused by, among other factors, filamentous fungi, ubiquitous molds belonging to Aspergillus spp. which are often opportunistic pathogens. Over 100 species of Aspergillus have been described. The most common species responsible for diseases in humans and animals are Aspergillus fumigatus and Aspergillus niger, with Aspergillus flavus and Aspergillus clavatus being somewhat rarer. Aspergillus causes a range of diseases, from localized colonization and hypersensitivity reactions, through chronic necrotizing infections, to rapidly progressing angioinvasion and dissemination, leading to death. Testicular mycosis is extremely rarely described in both humans and animals. No studies in the literature report a simultaneous occurrence of testicular tumors and fungal infection of the organ, so the aim of this paper was to describe, for the first time, a case of two independent testicular tumors coexisting with testicular mycosis. A histopathological examination was performed on the left testicle of a male dog, specifically a mixed-breed dog resembling a husky weighing 22 kg and with an age of 8 years. Bilateral orchidectomy was performed for medical reasons due to the altered outline of the left testicle, leading to scrotal deformation. The dog did not show any clinical signs of illness, and the testicles were not painful. The right testicle, according to the operating veterinarian, showed no macroscopic changes, so histopathological verification was not performed. Microscopic imaging of the changes clearly indicated the coexistence of a tumor process involving Leydig cells (Leydigoma, interstitial cell tumor, ICT), Sertoli cells (Sertolioma), and fungal infection of the testis. The case suggests the possibility of the coexistence of tumor processes, which may have impaired local immune response of the tissue, with an infectious, in this case fungal, inflammatory process. Based on the literature, this paper is the first report on the occurrence of two independent histotype testicular tumors and their associated mycosis.