Tyson is a nine-and-a-half-year-old Staffordshire bull terrier. It is difficult to tell he is that old since he still greets everybody and everything with the kind of rapturous welcome that leaves you wondering if a small tornado just hit you.

When he developed a lump on his bottom his owners at first did not notice and then did not worry since he clearly was not ill. Then one day the lump bled a little and they decided it was time to bring him along to see me.

He bustled into my consulting room with his usual vigour, delivering a thrashing from his tail as his owner lifted him on to my consulting table. One or two small treats provided a sufficient bribe to keep him still while I looked briefly at his bottom.

I found there were two lumps just under his tail. Older male dogs suffer from a group of problems around their back end connected with being male. I was pretty sure that the lumps on Tyson's bottom were benign tumours that grow from the glands in the skin that moisten and protect the skin.

These perianal adenomas, as these growths are called, hardly ever appear in bitches or in male dogs that have been neutered. Although they are benign they quickly burst through the surface of the skin and start to bleed, so much so that without treatment the whole bottom often becomes crowded with large bleeding lumps.

Just removing the lumps without doing anything else usually leads to them reappearing in just a few weeks, so the secret of successful treatment is to neuter the patient as well. Tyson's owners seemed more worried about him being castrated than about him having the lumps removed.

Even though modern surgery is very safe it is never very nice to have to face up to your own pet having to have an operation. After a little thought they agreed that he should have the operation. I was able to tell them that the castration would help to prevent some of the other problems that old male dogs can get, particularly prostate gland disease, hernias and tumours of the testicles.

I also reassured them that I thought it highly unlikely that castration would change his behaviour. He would probably be less aggressive towards other male dogs, but they were quite pleased about that.

Two days after I saw them, Tyson came in for his operation. All went well and he was able to go home the same evening. Two days later he came back for his check-up and then after another week for his stitches out. Slightly to his owner's surprise he never tried to lick his stitches.

I will be checking his bottom regularly for the next year, and his owner is taking particular care to see he does not over-eat and put on weight. his bottom healed fine and he is still just as enthusiastic at coming to the surgery.

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.