Prostatic cysts

From Dog
Paraprostatic pseudocyst. Bladder is to the right and prostate is lower left.[1]

Prostatic cysts (urine-containing prostatic cavitary lesions) are a relatively uncommon prostatic disease of entire and desexed male dogs.

Prostatic cyst often develop secondary to prostatic hyperplasia, where there is variable distension of prostatic acini to form cystic structures, and can form in dogs with no pathological evidence of prostatic disease[2]. They have also been reported in canine cryptorchidism[3] and perineal hernias[4]. A significant proportion have secondary bacterial infections. Histologically these cysts are lined by normal glandular cells.

Clinically affected dogs usually present with prostatomegaly-related signs such as tenesmus, constipation and flattened feces[5].

Diagnosis is based on rectal examination augmented with abdominal ultrasonography, MRI, and histopathology of tissue samples obtained during exploratory laparotomy[6]. Mineralization of paraprostatic cysts is more common than originally thought, and radiography is an important aspect of proper diagnostic workup to identifying the presence of these cysts[7].

Accidental diagnoses have also been made during routine cystocentesis, when fluid has inadvertently been collected from the prostatic cyst[8].

A differential diagnosis would include other diseases of the prostate such as prostatic hyperplasia, prostatitis and prostatic adenocarcinoma.

Treatment usually requires broad-spectrum antimicrobial coverage if indicated, such as cefovecin and surgical extirpation of the cysts. These dogs tend to require a more aggressive surgical therapy than percutaneous drainage alone[9]. Ultrasound-guided percutaneous drainage is usually recommended[10], or exploratory laparotomy with extirpation of the cystic prostate[11] and omentalization or marsupialization of the defect.


  1. University of Guelph
  2. Black GM et al (1998) Prevalence of prostatic cysts in adult large breed dogs. J Am An Hosp Assoc 34:177-180
  3. Mostachio GQ et al (2007) Intraabdominal torsion of a neoplastic testicle and prostatic cyst in a cryptorchid dog. Schweiz Arch Tierheilkd 149(9):408-412
  4. Head LL & Francis DA (2002) Mineralized paraprostatic cyst as a potential contributing factor in the development of perineal hernias in a dog. J Am Vet Med Assoc 221(4):533-535
  5. Ragetly GR et al (2009) What is your diagnosis? Discrete prostatic cysts. J Am Vet Med Assoc 234(9):1127-1128
  6. Goodrich ZJ et al (2011) Two cases of paraprostatic cysts in castrated male dogs. J Am Anim Hosp Assoc 47(6):e195-198
  7. Renfrew H et al (2008) Radiographic and ultrasonographic features of canine paraprostatic cysts. Vet Radiol Ultrasound 49(5):444-448
  8. Driver TL & Swenson CL (2010) Pathology in practice. "Urine" sample collected by cystocentesis probably fluid aspirated from a prostatic cyst. J Am Vet Med Assoc 236(9):957-959
  9. Bokemeyer J et al (2011) Prostatic cavitary lesions containing urine in dogs. J Small Anim Pract 52(3):132-138
  10. Boland LE et al (2003) Ultrasound-guided percutaneous drainage as the primary treatment for prostatic abscesses and cysts in dogs. J Am Anim Hosp Assoc 39(2):151-159
  11. Welsh EM et al (2000) Surgical management of perineal paraprostatic cysts in three dogs. J Small Anim Pract 41(8):358-361