Case Study

Prostatic abscess and Sertoli cell tumor in a 11 year old MN Labrador Retriever dog

An 11 year old MN Labrador Retriever canine (no descended testicles were present but this was an adopted dog with shelter history) was presented for progressive weight loss (4 pounds over a few months), hair loss, and leaking of urine. Abnormalities on physical examination were alopecia on the hind limbs and flanks and urinary incontinence. Leukocytosis, neutrophilia, monocytosis, eosinophilia, and thrombocytosis were present on CBC; blood chemistry and coagulation profile were within normal limits. Survey radiographs showed an enlarged prostate.

DX

Prostatic abscess and Sertoli cell tumor found in later sonogram in pelvis.

Sonographic Differential Diagnosis

Date 5/20: Prostatic abscesses with urinary tract infection. Possible concurrent carcinoma. Date 5/26: 70% resolved prostatitis and prostatic abscess. Persistent abscess re-drained. Potential remodeled retained testicle in the abdomen cranial urinary bladder caudal to the kidney.

Image Interpretation

Date – 5/20: The urinary bladder presented a large amount of debris with no evidence of calculi. A low grade cystitis pattern was noted. The prostate was significantly enlarged. It measured 6 x 7 cm with multiple abscesses and chronic parenchymal changes. There is the possibility of carcinoma. Date 5/26: The prostate was approximately 70% resolved with more uniform tissue and multiple abscesses have now resolved. A residual abscess was noted at 2.3 x 1.7 cm at the cranial aspect of the right lobe of the prostate. This was drained and approximately 3 cc of purulent material was retrieved and 2 cc of enrofloxacin was injected. The urinary bladder presented persistently minor chronic cystitis pattern, yet this was improved. A 2.1 cm iliac lymph node was prominent and consistent with lymphadenitis. A 2 x 1.6 cm echogenic, remodeled, round structure was noted cranial to the urinary bladder and caudal to the right kidney. This could be a residual retained testicle that has undergone infection or remodeling. Continuation of antibiotic therapy based on the beta hemolytic streptococcus and squamous metaplasia and septic suppurative inflammation would be recommended over the next 4 weeks with a recheck sonogram at that time.

Outcome

An injection of Baytril was given into the prostate via ultrasound and followed up with Baytril, Buprenex, and a fentanyl patch. The patient was discharged with Baytril and a low residue diet. Recheck ultrasound six days later showed an ongoing prostatic abscess, which was once again drained and 2ccs of Baytril instilled. The patient was treated with another course of Baytril. Recheck ultrasound and a testosterone level was recommended after one month. Upon further evaluation, a follow-up sonogram revealed a growing pelvic mass. The necessary approach was through the perineal inlet. A board-certified surgeon removed a pelvic Sertoli cell tumor and drained the prostate once again. The patient recovered well postoperatively.

Comments

The original Sertoli cell tumor was not seen on the prior ultrasound owing to its deep pelvic position. Retrospectively the sonographer should have obtained a perineal approach to the pelvic inlet during the initial examination. The suspicion for retained testicle was present in the initial thought process but could not be located from a transabdominal approach. Testosterone levels could have also been performed to confirm androgen production soliciting the prostatic enlargement and secondary abscessation/infection.

Note: No history of retained testicle was presented to the sonographe rat the time of the sonogram

Clinical Differential Diagnosis

Prostate disease – benign prostatic hyperplasia, prostatitis, abscess, neoplasia. Alopecia – endocrine disease (hyperestrogenism, hypo/hyper-testosteronism, hyperadrenocorticism, hypothyroidism). Lung opacity – pneumonia, edema, neoplasia. Weight loss – neoplasia, chronic inflammatory disease, organ failure, reduced intake, excessive loss.

Sampling

Ultrasound-guided drainage of abscesses was performed with injections of enrofloxacin (total of 4 cc) into the different cavities. Fine-needle aspiration of the parenchyma was also performed to rule out underlying carcinoma. Cytology of the prostatic abscesses was consistent with squamous metaplasia and septic suppurative inflammation. Culture of the prostatic sample yielded growth of Beta hemolytic Streptococci. Abnormalities on urinalysis from an US-guided cystocentesis were 2+ proteinuria, 1+ bilirubinuria, 3+ hematuria, and leukocyturia. The urine was dark yellow in color and had a turbid appearance with elevated microalbumin. Urine culture yielded growth of Beta hemolytic streptococci. Recheck ultrasound six days later showed an ongoing prostatic abscess, which was once again drained and 2ccs of Baytril instilled.