Sertoli cell tumors are unique testicular tumors that are known for their ability to cause feminization of male dogs. These tumors are commonly diagnosed via histopathology at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL). Usually, little clinical history is provided with these submissions, and usually only testicles are submitted. This article describes a case of Sertoli cell tumor in a dog with diagnostic features of hyperestrogenism syndrome seen in additionally submitted mammary gland and skin specimens.
The patient was a 9-year-old, male, Jack Russell Terrier, and TVMDL received four formalin-fixed biopsy specimens including both testicles, a mammary gland, and an unrelated dermal mass. Reported physical exam findings included alopecia, single mammary gland enlargement, and testicular asymmetry with one large, firm testicle and one small, soft testicle. Histopathologic examination was diagnostic for a testicular Sertoli cell tumor within the enlarged testicle, and the contralateral testicle was atrophied. The mammary gland specimen exhibited teat enlargement and mammary gland development with ductular and lobular hyperplasia. There were changes of endocrine dermatopathy noted in the skin of the mammary gland specimen and in the skin of the dermal mass specimen.
Sertoli cell tumors are common in dogs and are rare in other species. They classically occur in cryptorchid testicles, but they can also occur in descended scrotal testicles, as seen in this case. The incidence of Sertoli cell tumors is more than 20 times higher in cryptorchid testicles. Approximately 25% of dogs with Sertoli cell tumors exhibit signs of clinical hyperestrogenism syndrome, regardless of whether the tumors are in descended or cryptorchid testicles. Hyperestrogenism syndrome is due to production of estrogen by the neoplastic cells. Lesions associated with this syndrome include feminization, gynecomastia (male mammary gland development), testicular and penile atrophy, squamous metaplasia of the prostate, symmetrical alopecia, and/or bone marrow suppression. These clinical signs typically resolve following removal of the Sertoli cell tumor.
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REFERENCES
Agnew, D. W., & MacLachlan, N. J. (2017). Tumors of the genital system. In D. Meuten (Ed.), Tumors in domestic animals (5th ed., pp. 707-708). Ames, IA: John Wiley & Sons.
Foster, R. A. (2016). Male genital system. In M.G. Maxie (Ed.), Jubb, Kennedy and Palmer’s pathology of domestic animals (6th ed., pp. 494-495). St. Louis, MO: Elsevier.