Lump Directly Above Anus

Hi! I have a 10 year old Shih Tzu mix and about 2 years ago he developed a small pea-sized lump on the upper side of his anus. Didn't seem to hurt even if pressed  and never got any bigger. Eventually it want away. About a year or so ago a new one began directly above his anus but this one is about half the size of a super bouncy ball. It hasn't gotten any bigger than what it is and has been that way for about 4-5 months. It's solid with a little bit of fluid around it. It doesn't hurt him but I am worried it might be cancerous. THANK YOU!

Hello!   And I'm afraid that I am also concerned about this one.  Any lump may or may not be cancerous and if cancerous, it may or may not be the sinister sort that spreads around the body, and the way to find this out would be for your vet to sample it in some way. However, there is the additional issue of the location;  there is very little spare skin here and the lump is quite large.  If it continues to expand, then the issue of faeces constantly moving over it would need to be addressed.  The question of whether it is possible / preferable to remove needs to be raised;  I have seen lumps like this become rather sore.  I wonder if he is entire and whether hormones may be contributing? Anyway, whatever is causing it, it would be a good idea to see your vet sooner rather than later and ask about the full breadth of options available for you to consider.