Signalment & History
An 8 year old MN Bernese Mountain Dog presents with a history of hematuria and pain following urination. On physical examination, there is pyrexia and the abdomen is very tense preventing easy palpation.
Findings
There is well-defined, oval, soft-tissue mass located ventral to the caudal lumbar and sacral vertebrae in the caudal abdomen. The mass is causing dorsal displacement of the descending colon. The position of this mass makes it most consistent with prostate. The presence of mineralization within the prostate, along with the signalment (neutered, older male dog) makes prostatic neoplasia the most likely differential. There is smooth periosteal proliferation surrounding the body of one of the femurs.
Diagnosis
- Major differentials for prostatic disease include benign prostatic hyperplasia, acute or chronic prostatitis, prostatic abscess, intra- or paraprostatic cysts and prostatic neoplasia.
- Prostatic neoplasms are usually malignant; prostatic adenocarcinoma is the most common. Other types include undifferentiated carcinoma, transitional cell carcinoma, leiomyosarcoma, squamous cell carcinoma and lymphoma. Metastatic neoplasia can metastasize to the prostate. Also, urethral TCC can locally invade the prostate.
- Prostatic neoplasms commonly metastasize to medial iliac lymph nodes, periprostatic tissue, bladder, pelvic lymph nodes, lungs, mesentery and rectum.
- Prostatic neoplasia usually occurs in middle-aged or older, medium to large breed dogs.
- Prostatic neoplasia can occur in intact or neutered male dogs. Castration does not seem to be protective and in fact, prostatic neoplasms may be less differentiated and more likely to metastasize in castrated dogs.
- Dogs with prostatic neoplasia can present with a combination of urinary signs (hematuria, dysuria, incontinence), defecation abnormalities (tenesmus, constipation, dyschezia), systemic illness or locomotor abnormalities.
- On radiography, ill-defined prostate borders and increased opacity are suggestive of aggressive prostatic lesions. Mineralization can also occur in chronic prostatitis and prostatic calculi, however 80% of the time it occurs with neoplasia.
- Smooth periosteal proliferation of the femur is likely hypertrophic osteopathy secondary to the prostatic neoplasia.
- Ultrasonography, CT, MRI, and cytology/histology can help with diagnosis and staging.
References
Swinney (1998). Prostatic neoplasia in five dogs. Australian Veterinary Journal 76(10); 669-674.
