Paraprostatic cysts are epithelial-lined, fluid-filled structures found adjacent to the prostate gland (ie, extraparenchymal) in dogs. They have very rarely been reported in male cats.
Etiology and Pathophysiology of Paraprostatic Cysts in Dogs
Paraprostatic cysts result from embryological remnants of the female reproductive tract, found in males, which become fluid-filled.
Clinical Findings of Paraprostatic Cysts in Dogs
Clinical signs of paraprostatic cysts are similar to those noted with other types of prostatic enlargement and usually become apparent only when the cyst reaches a size sufficient to cause pressure on adjacent organs. Large paraprostatic cysts may result in abdominal distention and must be differentiated from the bladder and from prostatic abscesses.
Diagnosis of Paraprostatic Cysts in Dogs
Transabdominal ultrasonography with physical examination and hematologic findings will differentiate paraprostatic cysts from prostatic abscesses (see video illustrating transabdominal ultrasonography of the prostate in a dog). Paraprostatic cysts are generally larger than the inclusion cysts that can be a component of benign prostatic hyperplasia in dogs.
Treatment of Paraprostatic Cysts in Dogs
Medical treatment for paraprostatic cysts is ineffective. Castration alone is unlikely to be of benefit but may be indicated after the cyst has been removed.
Total excision of the paraprostatic cyst is the treatment of choice. If complete excision is not possible, the remaining portion of the cyst may be filled with a leaf of omentum secured with sutures. This omentalization of the cyst will provide internal drainage and lead to resolution. Surgical excision is preferable to marsupialization because chronic management of the marsupialization fistula is often problematic.
Key Points
Paraprostatic cysts are found adjacent to the prostate gland and result from embryological remnants of the female reproductive tract that become fluid-filled.
Clinical signs of paraprostatic cysts become apparent only when the cyst reaches a size sufficient to cause pressure on adjacent organs (eg, bladder, colon).
Medical treatment and castration are ineffective. Total excision of the paraprostatic cyst is the treatment of choice.
For More Information
Del Magno S, Pisani G, Dondi F, et al. Surgical treatment and outcome of sterile prostatic cysts in dogs. Vet Surg. 2021;50(5):1009-1016.
Park J, Won H, Park GG, et al. Laparoscopic treatment of paraprostatic cyst in two dogs: complete resection, and partial resection with omentalization: a case report. Front Vet Sci. 2024;11:1270819.
Also see pet owner content regarding prostatic diseases in dogs.
