Male dogs not neutered do develop circum-anal tumours sometimes.
This 13-year-old Silkie, male, not neutered has a gigantic tumour above and left of his rectum.
The dog wanted to bite me when I palpated the abdomen. X-rays show lots of chicken bone fragments fed by the father.
As regards the circum-anal tumour, the dog is very thin and old. So Tardak injections 2 weekly are advised to shrink the tumour a bit as it is uclerated. E-collar and antibiotics and to review in 2 weeks.
There is a group of dog owners who are against neutering the male dog. However, when circum-anal tumours develop and are small, get them removed by your vet. In such situations, the dog is old and so the owner may worry about death from anaethesia. In this case, the tumour is gigantic and bleeding. There is a stench from the dog's body as the tumour had ulcerated.