[Unilateral leiomyoma in the spermatic cord – a reason for intermittent colic in stallions?].

Unilateral enlargement of the spermatic cord caused recurrent colic signs in a stallion, and surgical removal followed by detailed tissue analysis identified the cause as a leiomyoma.

Case Description and Clinical Presentation

• A 19-year-old Oldenburg stallion presented multiple times over several months with recurring episodes of colic, which is abdominal pain often related to gastrointestinal problems.
• At every clinical examination, an enlargement of the right side of the scrotum was observed; the increase was noticeable both by palpation and visual inspection but could not be clearly identified using ultrasound or manual examination.
• The size of this scrotal swelling remained constant over time and did not change during the different episodes.
• There were no remarkable findings in the general physical examination or in examinations specifically targeting colic causes.

Progression and Diagnosis

• Several months after the initial colic symptoms appeared, a distinct mass, roughly the size of a chicken egg, was palpated on the right testicle.
• This mass was located dorsolaterally and extended towards the inguinal cleft, and it was clearly separate from the testicle itself.
• Along with recurring colic symptoms, the stallion’s sperm quality declined, indicating pathospermia, which is abnormal sperm characteristics often associated with reproductive issues.

Treatment and Histopathological Examination

• Due to the combination of repeated colic episodes and decreased sperm quality, the stallion underwent a hemicastration—the surgical removal of one testicle along with the associated structures on the affected side.
• The removed tissue, including the mass protruding from the testicle, the testicle itself, and the epididymis, was submitted for histopathological and immunohistological examination.
• Histopathology involves microscopic examination of tissue to identify abnormal cell growth, inflammation, or tumors; immunohistology uses special staining techniques to identify specific proteins to better characterize the tumor type.

Significance and Implications

• This case demonstrates that a leiomyoma (a benign smooth muscle tumor) in the spermatic cord can cause intermittent episodes of colic in stallions by possibly causing discomfort or mechanical effects related to the scrotal swelling.
• Such tumors may be difficult to diagnose with routine palpation and ultrasound as seen in this case, suggesting that persistent or unexplained scrotal enlargement in stallions with colic should prompt further investigation.
• The decline in sperm quality alongside colic signs highlights reproductive consequences associated with scrotal masses and justifies surgical intervention in affected breeding stallions.
• The case emphasizes the importance of considering extra-abdominal causes of colic and the role of detailed diagnostic and pathological examination to guide appropriate treatment.