It could be an external haemorrhoid or a skin tag. If it is leaking faeces, pus, blood or painful I would suggest you see a doctor for further examination. Colon cancer does not usually present with a lump outside the colon.
i also found a lump similar to the one described by bezzie. iv had mine for more than 2 years but it started getting painful recently. are haemorrhoids linked with cancer?
Get it checked out! I had what started as a small bump and thought it was a hemmoroid because I was always seriously constipated - it wasn't, it was stage II anal cancer! It would itch, sometimes hurt after itching, sometimes it would bleed bright red. I went to a new gyno and he wanted it checked out - didn't look quite right. I had it probably 3 years My doctor said it could have started out as a hemoroid then the irratation caused it to turn into cancer. So better saft then sorry...go get it checked out!