Case information:
The owner of a 5.5 year old intact male Golden Retriever is referred to you by his veterinarian. The dog has developed non-painful scrotal enlargement over the last 3 weeks. This is a valuable hunting dog, who is used regularly at stud and produces beautiful pups.
On physical examination, the scrotum is enlarged but not turgid or painful to the dog on palpation. The right testis is grossly enlarged and the left testis barely palpable.
Question:
What are rule-outs for scrotal enlargement in dogs?
Answer:
Testicular neoplasia is a common tumor of aged male dogs. The three most common tumor types are Sertoli cell tumor, seminoma, and Leydig (interstitial) cell tumor. All three are equally common in scrotal testes. Any tumor may cause an increase in intrascrotal temperature due to inflammation, with subsequent atrophy of the contralateral testis. Sertoli cell tumors also may induce atrophy of the contralateral testis as one component of a paraneoplastic syndrome, associated with estrogen secretion. Metastasis is uncommon. Diagnosis of neoplasia is by ultrasound but does not allow differentiation of tumor type. Treatment is castration.
Torsion of the spermatic cord is relatively uncommon in dogs and usually is associated with pain of the testis on manipulation. Diagnosis is by ultrasound (color flow Doppler may be used to great benefit in assessment of blood flow to affected tissues) or surgical exploration of the scrotum. Treatment is castration.
Canine brucellosis usually is associated with gross epididymitis and orchitis. Diagnosis is best made by serologic testing. Canine brucellosis is a zoonotic disease and is reportable in Minnesota. Treatment involves castration, housing away from susceptible animals and immunosuppressed humans, and intermittent antibiotic therapy to decrease shedding of the organism into urine or other body fluids.
Orchitis usually is associated with a history of penetrating injury or trauma, or may occur via hematogenous spread of bacteria. The affected testes are painful on manipulation. Diagnosis is by aspiration of the testis; many PMNs are present on microscopic examination of the aspirate. Treatment is castration.
Hydrocele / spermatocele are uncommon in dogs. Hydrocele is movement of fluid into the scrotum via the vaginal tunic. Spermatocele is formation of a fibrotic mass due to extrusion of spermatozoa outside the testicular capsule. Diagnosis is by ultrasound. Treatment usually is not necessary; hydrocele resolves spontaneously over time and spermatocele is quiescent.
Scrotal hernia is a manifestation of an inguinal hernia in which abdominal content move into the scrotum. Diagnosis is by ultrasound or surgical exploration of the scrotum. Treatment is surgical.