Hi, Penguins
You know, Bob asked a very pertinent question. My initial response to your query presumed a sore on the derma, not the shaft of the stoma. So...
My first (second, now?) thought is that perhaps the cut opening/edge of your appliance may be too close to the stoma and is rubbing and/or cutting into it frequently. I have had this happen, but the injury has been really minor and healed relatively quickly once I cut the opening of my appliance a little larger and paid really close attention to where I was positioning the appliance in relation to my stoma. Just over the last few months, I've noticed this issue. It confused me a bit at first, because most of us (ile)ostomates are told that a few months post-surgery, the size of our stoma will stop changing and settle into its "final" size. (Whether my stoma has actually changed size, again, 3+ years after my surgeries, I'm uncertain. It doesn't look like it has...so I'm guessing it's just...Operator Error. *chuckle*)
My second (third?) thought: are you very active, physically, where the appliance may shift ever-so-slightly in your movement and the cut edge of the appliance is "bumping up" against the stoma? Or, is there possibly undue pressure of anything against your stoma, maybe flattening it down so its surface has (greater) chance of contact with the cut edges of your appliance, creating injury? (Bob, these questions are for you, too. I think I remember reading that you're a very active person.)
The "mushrooming" also mentioned...could it be related to some of the sub-dermal intestine (in the abdominal cavity) working its way out through the stoma? If so, what is causing it? Good question for your doctors!
And maybe another ostomate will read all of the responses from the initial post, Penguins & Bob, and have another thought that leads to a solution for you. Be well, Gentlemen, and keep us posted on your progress!
Lily17