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HI this is DRB and I will try and help you with this. Any mass, or wound that grows on the anus needs to be either removed or biopsied as this is a location that tumors like to grow in. I looked at the pic but there is no way to diagnose this without a biopsy or removal or at the very least closer examination of mass under magnification. I know this is not what you wanted to hear but I would be remiss if I told you otherwise. Please let me know if you have any other questions that I can help with. Most Sincerely, DRB