2011: Colic associated with bilateral seminoma in a cryptorchid American Miniature Horse stallion


Colic associated with bilateral seminoma in a cryptorchid American Miniature Horse stallion 
R.A. Smith, L.K. Pearson, L.N. Wise, A. Tibary 

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State 
University, Pullman, WA 

 
 Equine testicular neoplasms are rare, likely due to the practice of early castration.  Testicular 
tumors originate from germ cells, sex-cord stroma, or other cells.  The most commonly reported testicular 
tumor in older (11 to 22 years, mean 16.5 years) cryptorchid stallions is seminoma.1  Most reported 
cryptorchid seminomas are incidental findings after cryptorchidectomy.  Reports of testicular tumors as a 
differential for a colic syndrome, such as in this report, are few.  

A 13-year-old bilaterally cryptorchid American Miniature Horse stallion was referred to the 
Washington State University-Veterinary Teaching Hospital for colic of 12 hours duration.  Initial 
evaluation demonstrated normal heart rate, decreased gastrointestinal borborygmi, and a small volume of 
nasogastric reflux.  Transabdominal ultrasonography revealed moderate small intestinal distention, 
thickened intestinal walls, and associated ileus.  Two large masses of heterogenous echotexture were 
presumed to be the cryptorchid testes due to their location.  Abdominocentesis, complete blood count, and 
serum biochemistry panel were consistent with chronic inflammation.  Despite medical therapy with 
intravenous fluids and non-steroidal anti-inflammatories, the horse remained depressed and mildly painful 
with ongoing nasogastric reflux.  Exploratory laparoscopy was performed and demonstrated a non-
strangulating compression of the jejunum by the right testis, which accounted for the clinical signs.  
Bilateral cryptorchidectomy was performed.  The horse recovered uneventfully from surgery.  
Histopathology confirmed malignant seminoma in both testes.  Further diagnostics to identify metastases 
were declined by the owner. 

Often in clinical practice, differential diagnoses for colic overlook reproductive etiologies.  In this 
case, the history of cryptorchidism assisted clinicians in making the decision to pursue surgical therapy 
for colic.  This case presented several unique features not commonly reported: bilateral cryptorchidism in 
an older stallion, neoplasia of both retained testes, and presentation to the veterinarian for colic signs.  
This case also raised issues of welfare in cryptorchid stallions and reinforces the importance of client 
education to seek removal of cryptorchid testes. 
 
Keywords: Equine; testes; neoplasia; pathology; laparoscopy; ultrasonography 
 
Reference 
1. Valentine BA: Equine testicular tumours. Equine Vet Educ 2009;21:177-178. 
 

Clinical Theriogenology • Volume 3 Number 4 • December 2011601



Clinical Theriogenology • Volume 3 Number 4 • December 2011 602


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