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Date:   20 August, 2010  
Focus: Small animals - dogs, cats, hamsters, guinea pigs & rabbits
TESTICULAR TUMOURS IN THE MALE DOG - Follow-up on one case of Sertoli Cell Tumour
Dr Sing Kong Yuen, BVMS (Glasgow), MRCVS
20 August, 2010 
Be Kind To Pets
Veterinary Education
Project 2010-0129
First report is at Tumours in 3 male dogs - Sertoli cell tumour, circum-anal tumour and oral tumour

"The young intern has no experience in dealing with the submission of specimens for histopathology," I explained to the Laboratory girl who phoned me to tell me that the 7 testicular specimens must be correctly labelled as "right" and "left" testicle when I queried the report's findings. My histopathological samples are sent to a commercial laboratory that specialises in this subject.

How come there was a blunder? It was my policy of letting interns be more hands-on.
I had instructed my assistant, Mr Saw, to let vet interns have some hands-on experience rather than being an observer. In that way, they will learn from experience and mistakes. We all learn every day as we can't be perfect people.

Ms Lai, the intern, would be studying veterinary medicine next year and so we gave her the task of submission and filling out the forms. She had been with us for around 2 weeks and had seen submission of blood samples. 

Well, the undescended testicle of this 6-year-old Retriever was enormous (half the size of a tennis ball) and would not fit into the usual container we used to submit samples for histopathology. So, I advised cutting it into 3 smaller pieces for the larger testicle (left) and 4 smaller pieces for the descended atrophied testicle (right).  

I ought to have advised getting a bigger container. I did that eventually. Next time I asked my assistant to check before submission of the samples. Usually we submit one sample and it fits nicely inside the Lab-provided bottles.

Everybody learns from being hands-on. Young interns can't be spoon-fed all the time and will make some mistakes. It is part of growing up in life.

I was fortunate to have worked in the Vet Diagnostic Lab at Kampong Java Road (now the new Kandang Kerbau Hospital) as a new graduate in 1977 and so knew a bit about the work of histopathology. What had happened was that the intern put 7 pieces 1 big bottle and submitted the bottle and form without separation of the left and right testicle.

After receiving the histopathology reports, I phoned to clarify that there were two testicles submitted as the report had presumed I had submitted 7 pieces of one testicle. The report was then corrected as follows:

Specimens 1-4 are left undescended testicle. Specimen 5-7 are the atrophied descended right testicle. The histopathology results are as follows:
Takes a long time to pee. Painful enlarged prostrate when digital examined via rectum during light anaesthesia. Could this be purulent prostatitis as mentioned in:

Hyperpigmentation in the preputial area

Follow up 7 days later: Owner is happy. "No more limping now. We thought he had hip dysplasia."
I asked" Was the dog attracting other dogs during exercise outdoors?"  The owner recalled that many dogs wanted to make friends with him (the effects of hyperestrogenism).

Left testis - Sertoli cell tumour (see comments below). Right testis - Atrophy of the contra-lateral scrotal testicle resulting in aspermatogenesis.

Comments from the Histopathology Lab:
1. The left testis is extensively replaced by a tumour which is composed of closely packed tubules, trabeculae and nests of elongated spindly cells. A second interstitial (Leydig) cell tumour component cannot be excluded. Most primary testicular neoplasm in dogs are benign. The rare malignant Sertoli cell tumours have no good cytological or histological markers of malignancy. The vet needs to identify metastases in lymphatics, spermatic cord, lymph node or distant sites. Please correlate with clinical features.

Dr Sing's comments: The left testis will likely be a mixed tumour with Sertoli and interstitial cells involved). Much more details of the types of testicular tumour in the dog are in an excellent report at:

2. In the right testis, the parenchyma shows closely packed seminiferous tubes composed solely of Sertoli cells without spermatogonia, spermatocytes or spermatids. This is common in cryptorchid (undescended) testis. There is no tumour involvement.

1. As the histopathologist is an independent service provider, he or she had not seen the real dog. The right testis was assumed to be an undescended or cryptorchid testis. It was a descended testicle, much shrunken.

2. Hyperestrogenism. The reason the descended right testes was atrophied and had no sperm production was due to the excessive production of estrogen by the large left testicular tumour. Estrogen is anti-androgenic and therefore cause the atrophy of the scrotal right scrotal testes.

3. Blood test results as shown below indicated a thrombocytopenia which can be a cause of death in the dog if the tumour had not been detected early and removed.

sertoli cell tumour golden retriever swollen lump belly testicular tumour singapore toapayohvetsGolden Retriever, Male, 6 years. Left undescended testicular tumour and atrophied right scrotal testicle removed 5 days ago. Greyish-white, large sized and multi-nodular suggestive of a Sertoli cell tumour.
The owner asked about post-op management. This depended on blood test results.

Blood tests:
1. No disorders of liver and kidney function. Glucose is normal.
2. Haematology: Low haemoglobin and red cell count. Low PCV. Very low platelet count. Platelet clumping noted. (This indicated bone marrow depression). Effects are well written in:

Urine results
1. pH=7.0, SG 1.027.
2. Abnormal findings: Protein 2+, Glucose 1+, Blood 4+, WCC >2250/uL, RBC 900/uL, epithelial cells 1053/uL. Bacteria 3+

This indicated a severe bacterial infection of the bladder and prostate (painful and enlarged during rectal palpation and presence of "epithelial cells"). The infection is localised to the urinary tract as the total blood White Cell Count was OK. The dog had been given IV Vit K1 in drip earlier and appeared much more energetic the next day. Diagnosis would be urinary tract infection (UTI). But the cause was the testicular neoplasm (hyperestrogenism leading to bone marrow depression and prostatitis with consequent UTI).

Advices to owner:
1. Had been fed meat, rice 1X/day in the past. Very thin. Increase feed to 2x/day.
2. Good quality premium dog food dry to be added. 1 egg/day for 14 days.
3. Antibiotics for next 14 - 20 days. UTI + prostatitis + bone marrow depression.
4. Review in 14 days.

Some 10 days later, the owner said that the dog was normal and active. "I thought he had hip dysplasia," he told me over the phone. "He was walking with a limp."

4. More info of this case has been recorded at:
Tumours in 3 male dogs - Sertoli cell tumour, circum-anal tumour and oral tumour

5. An excellent veterinary report on canine testicular tumours is at:

I note that the "Summary" stated that "the Sertoli cell tumour is the only known testicular tumour that commonly produces hormones with clinical effects." Some vet reports I read on the internet claim that estrogen is produced by two of the 3 common testicular tumours, namely the Sertoli cell tumours and Seminomas.  In the "Introduction", there was this statement that "testicular neoplasms other than Sertoli cell tumours are rarely hormonal productive. Testicular neoplasms are often mixed-origin especially in cryptorchid testes". In this case, the histopathologist indicated that the undescended testicle could be a mixed type with Sertoli cell tumour and interstitial (Leydig) cell tumour.

Cryptorchidism (undescended testicles)
 in the dog can be unilateral or bilateral

Testicular tumour in a 10-year old dog

Note that the above-mentioned article said that testicular neoplasm in the dog is presented early as 6 years of age (as in this case-study) but the median age is 10 years (photo of one of my cases, right). 

Testicular Tumour in an undescended testicle of a 10-year-old Spitz in my 2001 case when I was new into digital photography.  This 9-year-old picture is not acceptable as good photography by me nowadays but it is the only one left for illustration to vet students.  

In 2010, many younger dog owners do not wish to have their male dogs neutered as they perceive the surgery to be cruel. However, undescended testicles may develop testicular tumours. Weekly check up of the dog's belly will detect their presence  

Undescended left testicle is a Sertoli tumour. 8 year old Jack Russell. Toa Payoh Vets

Testicular Tumour in an undescended testicle of an 8-year-old Jack Russell. The contra-lateral testicle is atrophied. Check the belly of your older dog every week if you do not wish to have your male dog neutered. Testicular tumours are seldom malignant but they do cause death due to bone marrow depression and thrombocytopenia and consequent overwhelming bacterial infections.


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