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Collagen Nevus

22 11:27:37

Question
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Followup To
Question -
Hi Dana,
You were kind enough to help me 6 months ago, when I lost my precious Peanut, I have never forgotten your compassion and knowledge.Thank you.
So, I have another problem.
I have a approx. 6 year old New Zealand rabbit, Bun Bun. He was abandoned, left without food and water on a sunny patio.He has always had lumps all over his body, and has been diagnosed with Collegan Nevus.
Five months ago, a hole appeared on his side approx. 1" in diameter.After seeing numerous Vets, he was stitched and stapled 10 times, but kept opening up to an ever largening hole, till we finally convinced a Vet to operate, which she did, and found a massive hematoma and a hole the size of a lime. She managed to repair all the damaged tissue, and eventually he healed.Still don't know why the hole appeared.
Since then, he is still bald on that side, and he has had two surgeries to remove lumps that seem literally to appear overnight growing at an alarming rate, which he tries to chew off.There has never been an infection, thank goodness.
When we put a collar on him, he has chronic diarrhea.
I can't seem to find any article on this on the Internet. Do you know of anything that will help Bun Bun, this has to be very painful for him, and is this common to Collagen Nevus, or is there some other problem occuring.?
I would really appreciate your help. Sadly it is very difficult to find a true rabbit Vet.
Thank you Dana,
Would be grateful for your thoughts.
Gina
Answer -
Dear Gina,

Wow, this is a really weird problem.

Connective tissue nevi (plural of nevus) are benign skin growths that can be composed primarily of any of several of the components of skin tissue (e.g., collagen, elastin, etc.).  Your bunny seems to have the collagen type.  No one knows what causes this, and some bunnies are prone to them.

In my experience, the connective tissue nevi are not fast-growing, but your bunny's experience seems to be different!  Have any of the lumps actually been biopsied, or is the vet making the diagnosis based on gross analysis?  If no biopsies have been done, this might be useful, in case the problem is not actually connective tissue nevi.  You can find a pretty good overview of the condition here:

http://www.emedicine.com/derm/topic83.htm

The hole in the side is really bizarre.  This poor bunny seems to have suffered a lot, and I wonder how many of his problems are due to malnutrition and neglect that are just now being resolved with the good care you're giving him.

On the other hand, he *is* a New Zealand rabbit.  These are used for laboratory studies, and are quite inbred.  It's possible he might have some recessive genetic condition that's resulting in his very odd pathology.  The diagnosis of "collagen nevi" is sort of a descriptive one, and doesn't really indicate a specific "disease" with a known cause--possibly because there isn't a single known cause.

Putting a bunny in an E-collar is usually not a good idea.  As you've noticed, they get stressed and get cecal dysbiosis:

www.bio.miami.edu/hare/poop.html

and can't reach the normal cecotropes properly to eat them.

Are the vets you're working with very experienced with rabbits?  (You intimate they're not, and the fact they're using staples in rabbit surgery--a BIG no-no among truly experienced rabbit vets--confirms this).

Have you tried to find a rabbit vet with the lists here:

www.rabbit.org/care/vets.html

I hope that will help.  Please write back if you have any other questions.  

Dana


Hi Dana,
Thank you for replying,
We have had Bunbun for 6 years, and his appetite has never been effected.He weighs a healthy 7 and a half pounds, he is not overweight, and eats only the best bunny things.
The Vet did take two of the lumps for biopsy, and it came back as Collegan Nevus.
I have been to every Vet who sees exotics in the County, I have even taken him to Dr.Hess at Winterpark, which is 300 miles away. I am truly at a loss, as to what more I can do, apart from wiping the blood away when he chews at his bald areas where he can see the lumps, keeping it clean, and having them removed when he half chews them off.
Any suggestions?
The Vet who stapled him, I have not been back to, and once the Emergency Vet stapled him, when he was waiting for surgery, and the wound was gaping and had depris,(hay) inbedded in it, so she had to flush the wound also.
During the course of the years, before his hole appeared, the lumps would get smaller and larger, sometimes some would go, then return.
I have never encountered anything like this. Poor Bunbun, he is the most loving bunny.
Will wait for your reply, can send photos if it would help, then I have a question about my Dinky.
I think i am keeping you busy.
Thanks Dana,
Gina

Answer
Dear Gina,

Boy, if Dr. Hess can't handle it, I'm at a loss.  Bunnies may start to express weird genetic conditions as they age, and I suspect this is what's happening to Bun Bun.  Perhaps it's just a cross he'll have to bear.  :(

As long as he's eating well, and you're getting the problematic lumps treated promptly, I think you're doing everything you can do.  He's a very lucky bunny to have such a caring mom!

Dana