Draught and draught‐related breeds are also affected by testicular teratoma: A retrospective study on cryptorchidism

Summary Background There is limited information regarding cryptorchid teratomas other than a few case report studies, and almost all involved standard‐frame horse breeds. Objective To investigate the prevalence of testicular teratoma in horses presented for cryptorchidism and to determine its relationship with horse breeds. Study design Retrospective case series. Methods Medical records from all horses presented for cryptorchidism that underwent surgical cryptorchidectomy between January 2010 and August 2021 in a single institution were reviewed. Additionally, cryptorchid horses with a histopathological diagnosis of testicular teratoma were further analysed. Results Cryptorchidectomy was performed in 220 horses (253 testicles: 187 unilateral and 33 bilateral). Left abdominal cryptorchidism was the most common presentation (101/187, 54%), followed by right abdominal (37/187, 20%) and then, right (27/187, 14%) and left (22/187, 12%) inguinal. A teratoma was confirmed via histopathology in two Draughts, one Draught‐related breed (Canadian horse) and one Paint. Unfortunately, a pre‐operative diagnosis of teratoma was not reached in 3/3 horses where only routine caudal ultrasonography was performed. Draught and draught‐related breeds represented 6% (2219/36,857) of the hospital caseload during the study period and 11% (24/220) of the entire cryptorchid population. Draught and draught‐related breeds had a 37.1 relative risk ratio of having a cryptorchid teratoma (95% CI: 7.85–175.73) in this study. However, this may have been coincidental or specific to our geographic location given the small number of affected cases. Main limitations Retrospective nature of the study, small population of horses, one institution and by extent one geographical location. Conclusions We found that cryptorchid teratomas are encountered with a high prevalence in our draught and draught‐related breed caseload. A thorough pre‐operative ultrasound, including cranio‐ventral abdomen, may be recommended in cryptorchids to facilitate identification of large teratomas lying cranially within the abdomen as well as surgical planning.