Unilateral testicular enlargement in a 5-year-old Arabian stallion.

This study presents the case of a 5-year-old Arabian stallion with unilateral testicular enlargement due to a 360° spermatic cord torsion, which was initially misinterpreted as severe colic. The condition was diagnosed with the aid of ultrasound and Doppler ultrasonography and was treated with hemicastration without complications.

Case History and Physical Examination

• A 5-year-old Arabian stallion was brought in due to severe colic signs observed by the owners and their veterinarian.
• The physical examination by the referring veterinarian noted a mildly enlarged left testicle that was firm and cool to the touch.
• Upon hospital admission, the horse showed no signs of colic, and all vital signs, as well as blood parameters, were normal.
• However, it was noted that the left testicle was slightly larger than the right one, and it was firm, cool, and did not cause pain upon palpation.

Diagnosis and Hospitalization

• Palpation and ultrasound examination revealed a mild enlargement of the left spermatic cord, irregular echogenicity in the testicular parenchyma, and a substantial reduction in blood flow compared to the right one.
• These findings led the veterinarians to suspect a spermatic cord torsion, but given the lack of colic signs, other testicular abnormalities were also considered.
• The horse was hospitalized for observation and successive examinations. After 36 hours, the strenghtened edema and worsened echogenicity of the left testicle, along with the decreased blood flow of the left spermatic cord, confirmed a diagnosis of a 360° spermatic cord torsion.

Treatment and Outcome

• The horse was prepared for a hemicastration procedure, which included the administering of preoperative antibiotics and anti-inflammatory medication, and a tetanus toxoid.
• Following general anesthesia, the left testicle was removed and sent for histopathology, showing ischemic necrosis in both the testicular parenchyma and the spermatic cord.
• The horse showed no complications postoperatively and remained in the hospital for three additional days before being discharged to its farm with a set of care instructions.

Discussion

• 360° spermatic cord torsions are considered emergencies as they compromise the vascular supply to the affected testis, leading to edema and pain, and potentially mistaken for gastrointestinal colic. This misinterpretation occurred in this case.
• However, cases of ≥ 360° torsions of the spermatic cord may not always be painful, as observed in this case where the initial colic signs and pain subsided rapidly.
• Therefore, increased scrotal edema and serial ultrasound examinations to observe changes in the echogenicity of the testicular parenchyma and blood flow were more useful indicators of a ≥ 360° torsion of the spermatic cord.
• Given the differential diagnoses in horses with unilateral scrotal enlargement, thorough examination and diagnostics are necessary to identify this condition.
• Timely hemicastration is vital, especially for horses with breeding value, to ensure the preservation of their fertility.