Assessment of the prostate gland; transrectal palpation
Keywords: canine, dog, prostate, radiology, hyperplasia, neoplasia, palpationThe canine prostate gland is frequently affected by hyperplasia, cystic development, infection and neoplasia.
Using ultrasonography for measurement (the gold standard in this regard), the size of the prostate in a 15 kg dog is approximately 3.4 cm long and 2.8 cm dorsoventral and 3.3 cm in diameter. There is however, a highly significant correlation between body size and the size of the prostate gland. An accurate assessment of size can be calculated by using a formula for volume of an ellipsoid i.e. volume = length x width x height x 0.523. For details, refer to Ruel et al. 1998. Ultrasonography is also very valuable in detecting prostate pathology.
Before ultrasonography or any other procedures (radiology, flushing, cultures etc) are performed, the prostate should always be examined by transrectal palpation. Palpation of the prostate (Figure 1) is also a routine practice in breeding soundness evaluations and is used to collect prostate fluid samples to diagnose prostatitis.
The prostate is an ovoid-spherical structure that surrounds the urethra just distal to the bladder. It is bi-lobed and has both a dorsal and ventral sulcus, only the dorsal sulcus being palpable. The prostate gland is far smaller in castrated dogs than intact dogs, shrinking to castrate size within 6 months at most. Therefore neoplasia or other pathology should be suspected if the prostate is enlarged or irregular in castrated dogs.
Selected references:
Barsanti, J. A. and Pineo, D. R. 1986. Canine prostatic diseases. Vet Clinics of North America:Small animal practice. 16: 587-599
Ruel, Y. et al. 1998. Ultrasonographic evaluation of the prostate in healthy intact dogs. Vet Radiol. Ultrasound 39: 212–216.
Smith, J. Canine prostatic disease: A review of anatomy, pathology, diagnosis, and treatment, Theriogenology 70 (2008) 375–383
