Paraprostatic Cysts (Prostatic Cysts) in Dogs

Overview of Canine Paraprostatic Cysts (Prostatic Cysts)

Paraprostatic cysts are fluid-filled sacs found adjacent to the prostate and are connected to the prostate by a thin stalk or tissue adhesions. The cysts are an uncommon occurrence in male dogs, and are very rare in cats. They are developmental in origin, and arise from remnants of fetal tissue (uterus masculinus) that normally degenerates during development. If this degeneration does not occur, a paraprostatic cyst might develop. The cyst can also be directly of prostatic origin.

Single or multiple cysts may be seen, and they can get very large. Animals usually only feel ill if the cysts become large enough to compress other internal organs or if they become infected. If a cyst becomes infected a prostatic abscess could develop. Some paraprostatic cysts may contain blood and these are called hemacysts.

Estrogen, either given orally or produced within the body, as in a Sertoli cell tumor, has been associated with cyst formation.

Many times paraprostatic cysts are incidental findings and animals are not symptomatic. Symptoms occur when a cyst becomes infected or it gets large enough to place pressure on other structures. The colon or urethra, which is the tube that carries urine from the bladder through the penis and out of the body, may become compressed and lead to clinical symptoms.

What to Watch For

Symptoms of Paraprostatic Cysts (Prostatic Cysts) in Dogs may include:

• Straining to defecate (pass stool)
• Straining to urinate
• Abdominal distention
• Swelling in the perineal area (area under the anus)
• Blood in the urine
• Discharge from the penis that is either bloody, cloudy, yellow or clear
  Occasionally an animal may experience urinary incontinence.

Diagnosis of Paraprostatic Cysts (Prostatic Cysts) in Dogs

• History and physical exam including digital rectal exam
• Complete blood count
• Biochemical profile
• Urinalysis
• Culture and sensitivity of the urine
• Cytologic (microscopic) evaluation of seminal or prostatic fluid, collected by ejaculate, with culture and sensitivity
• Prostatic massage and wash for cytology, and culture and sensitivity
• Abdominal radiographs (x-rays)
• Distention retrograde urethrocystography (a radiographic technique where dye and air are injected through the urethra and into the bladder) may help differentiate the cyst from the bladder
• Abdominal ultrasound with or without aspiration (Inserting a needle and syringe into the cyst and obtaining a small sample for cytologic analysis) of the cyst. Extreme caution must be used if an abscess is suspected.
• Surgical exploratory

Treatment of Paraprostatic Cysts (Prostatic Cysts) in Dogs

• Intravenous fluids may be required if the animal is dehydrated, or has a urinary obstruction.
• Urinary catheterization if the cyst is causing a urinary obstruction
• Antibiotics may be needed to treat secondary bacterial infections
• Exploratory surgery for surgical drainage or marsupialization (creating a pouch) and or removal of the cyst. The best, most effective treatment is the complete removal of the cyst, if surgically possible.
• Castration

Home Care and Prevention

The drainage area should be watched closely, and cleaned several times a day. Recheck examinations are important to make sure there is proper healing and monitor the amount and type of discharge. If drains were placed, they are generally removed in a few weeks.

Cultures of urine and or prostatic fluid might be recommended after finishing the antibiotics if there was a secondary bacterial infection.

Unless the cyst could be completely excised (removed) recurrences are common. Abdominal ultrasounds can be done to evaluate for potential recurrence.

Neutering a dog before reaching sexual maturity may decrease the incidence of paraprostatic cyst formation.