Tuesday, August 10, 2010

156. Tumours in older male dogs

On Aug 11, 2010. I reviewed the 3 cases to find whether they are linked to the male gender. Dogs over 6 years of age are more likely to develop tumours than younger ones. The following three cases are recorded to educate dog owners and help veterinary students in their studies.

1. Maltese, Male Dog, 18 years old
Circum-anal tumour above anus
One testicular tumour 3.5 cm x 2.5 cm x 2.0 cm was sent to the Laboratory for histopathology.

Due to economic reasons, I submitted the testicular tumour and not the other normal sized testicle.
Result: Malignant tumour compatible with a seminoma.
Interstitial Cell Tumours and Seminomas are reported to produce estrogen. Dog has a very good coat. Could it be due to excessive estrogen production?
The circum-anal tumour is more common in male, non-neutered dogs.

2. Labrador Retriever, Male Dog, 6 years.
Retained or undescended left testicle grew explosively to half the size of a tennis ball while the right testicle was shrunken (atrophied). Sent both for histopathology. The dog goes home tomorrow (5th day after neutering). Blood tests and histopathology in progress.

From the appearance, the testicular tumour is a Sertoli cell tumour. Sertoli cell tumours tend to grow very large. They are firm, white or greyish and multinodular. The rate of metastasis is reported to be less than 10%. Early removal will give the dog good chances of survival. I believe that this 6-year-old dog's testicular tumour had been detected at an early stage* by the father or family member. If the histopathology results show a diffuse subtype as contrasted to the intratubular subtype. We have to wait and see. A young lady owner is concerned.
* Around 1/3 of dogs with Sertoli cell tumours show signs of hyperestrogenism (feminization, gynecomastia, atrophy of the contralateral testicle, squamous metaplasia of the prostate and prostatitis, symmetrical alopecia from genital area to cranio-dorsally and bone marrow atrophy.

In bone marrow atrophy - initial transient increase in granulocytes and neutrophils followed by leucopenia, thrombocytopenia and non-regenerative anaemia and granulocytopenia. Death from overwhelming bacterial infections and bleeding.
This Labrador Retriever had atrophy of the contralateral testicle, prostatitis (ping-pong ball sized prostate and pain on digital rectal examination, takes a long time to pee). Will wait for blood test results.

A good report on testicular tumour is at: www.vet.uga.edu/vpp/clerk_anat/sabatino/index.php

3. Miniature Schnauzer, Male Dog, 11 years.
Bad breath complaint in Jun 2010. I had excised large cheek tumour in Jun 2010. Extracted 15 teeth and dental scaling done. The case is recorded at:
Some pictures are shown as follows:

"There is a white lump in the same area of his previous tumour," the young lady said today. "He would not allow me to open his mouth. I saw it when he yawned." The dog would not permit me and my assistant Mr Saw to open his mouth too. He jerked away suddenly when I gripped his upper jaw. No point fighting and getting bitten. I will sedate and check mouth and teeth. Recurrence of oral tumour likely. Did not send the previous tumour for histopathology to reduce the veterinary costs for the owner.

The dog had no fever but vomited and had diarrhoea 4 X yesterday. The dog will be treated for gastroenteritis first before any exploration of the mouth.

"Oral tumours are associated with the many years of poor dental hygiene," I said to the young and slim lady who does sales. "My advice to neuter him is not to prevent recurrence as this oral tumour. I have not heard of any scientific studies regarding neutering and oral tumours. However, any dog over 6 years of age is likely to develop tumours. Since your dog has a large cheek tumour, I advised neutering to prevent testicular tumours.

"it is well known that neutering of the male dogs do prevent or lower the incidence of circum-anal tumours and the development of testicular tumours in testicle that have not come down from the body into the scrotal bag."

I doubt that this young lady know what I am talking about. I elaborated: "Since this dog has developed such a large oral tumour, it is best to remove his testicles in case he develops testicular tumour. I am not guaranteeing that castration will prevent recurrence of the oral gum tumour and mouth ulcers."

The dog was warded, given the IV drip and medication for diarrhoea and vomiting.

I checked the anaesthetic records for the Jun 2010 cheek tumour (4.5 cm x 4.5 cm x 0.8cm) excised by electro-surgery for reference. Blood test normal results.

BW 12.3 kg
Domitor 0.2 ml IV
Zoletil 100 0.1 ml IV. Body tremors started. Gave Atropine 0.5 ml IV. Tremors stopped. Surgery done. Antisedan 0.2 ml IV. Dog woke up fast.

3 male dogs had tumours.

Case 1 - Maltese not neutered. Malignant Seminoma and Circum-Anal tumour. During his old age, he developed testicular tumour (malignant) seminoma and circum-anal tumour. Both were removed and the dog had no anaesthetic problems although he was 18 years old. I used isoflurane gas only. Neutering would have prevented such tumours from developing.

Case 2 - Labrador Retriever not neutered. Testicular Tumour. Surprisingly, at 6 years of age, he developed the testicular tumour so rapidly. Testicular tumours usually happens in dogs of 10 years. Studies have associated testicular tumours may form in undescended tumours (cryptorchidism) in man and male dogs.

Case 3 - Miniature Schnauzer not neutered. Oral tumour was large. Oral tumours develop due to poor oral hygiene in dogs and man, according to several medical reports. There is no association with neutering or no neutering. Teeth cleaning every alternate daily and yearly dental check up most important for your dog if you want to prevent oral tumours from developing in your dog.



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