Marion DuPont Scott Equine Medical Center, PO Box 1938, Leesburg, Virginia 20177, USA.
Unilateral testicular mastocytoma in a Peruvian Paso stallion
Article first published online: 5 JAN 2010
2008 EVJ Ltd
Equine Veterinary Education
Volume 20, Issue 4, pages 172–175, April 2008
How to Cite
Brown, J. A., O'Brien, M. A., Hodder, A. D. J., Peterson, T., Claes, A., Liu, I. K. M. and Ball, B. A. (2008), Unilateral testicular mastocytoma in a Peruvian Paso stallion. Equine Veterinary Education, 20: 172–175. doi: 10.2746/095777308X291741
- Issue published online: 5 JAN 2010
- Article first published online: 5 JAN 2010
A 12-year-old Peruvian Paso stallion was examined for scrotal swelling and unilateral testicular enlargement of 4–6 weeks duration. Physical examination and ultrasonography of the scrotum revealed an enlarged, nonpainful right testis with a well encapsulated mass at the cranial-medial aspect containing echodense flocculent material. Unilateral castration was performed and the testis, spermatic cord and vaginal tunic were submitted for histological examination, which revealed a mastocytoma with accompanying evidence of malignancy. Short-term follow-up examination did not reveal any evidence of abdominal metastasis and the stallion has since successfully achieved pregnancy in a small number of mares. Although considered rare, mast cell neoplasia should be considered as a differential diagnosis when unilateral testicular enlargement is encountered.