Malignant Schwannoma (nerve Sheath Tumour)

[labsrule]

My 12 year old black lab boy Thomas had surgery on Monday to remove a lump on the back of his left front leg as well as a small growth on the lower eyelid of his left eye. Received the results of the biopsy of lump removed from his leg today when I took him back for his post surgery check and he has been diagnosed with a malignant Schwannoma (Nerve Sheath Tumour). I was half expecting the maligancy verdict as the lump was a pretty solid mass and grew very quickly as I didn't notice it until it was a decent size due to the position of it being obscured in part on the back of his leg and it didn't affect his mobility at all. Anyway Vet advised it is a relatively rare tumour and is locally invasive so does not undergo metastatic spread, but can regrow and if that happens, then he will need further surgery to remove the regrowth. If it continues to regrow after multiple surgeries then amputation needs to be considered. My vet advised in the last 13 months, my boy is only the 2nd dog that has been diagnosed with this condition and the first dog which had surgery about 12 months ago has not had a regrowth occur yet, so that is good news.

As part of my research, I would like to know if any dolers dogs have been diagnosed with this condition? and if so, can you share your dog's experience/treatment on how they fared with this condition.

[Rappie]

I have removed one, it was between the dog's thoracic inlet and the point of it's shoulder - about the size of a tennis ball. It was doing fine for the few months after surgery, but I'm not sure what happened after that as I moved to a new practice. The histopathology indicated that it was removed with clean margins. As you've mentioned, they are locally invasive and it is quite unusual for them to spread to other parts of the body.

[labsrule]

I have removed one, it was between the dog's thoracic inlet and the point of it's shoulder - about the size of a tennis ball. It was doing fine for the few months after surgery, but I'm not sure what happened after that as I moved to a new practice. The histopathology indicated that it was removed with clean margins. As you've mentioned, they are locally invasive and it is quite unusual for them to spread to other parts of the body.

tks for your response Rappie, I will continue my research as it doesn't appear any dolers that read this section have had a dog with this condition, which I am not surrised at, given it's relative rarity. My vet was also pretty confident that they had removed the lump with clean margins as well, so here's hoping that it will not regrow quickly or at all.

[Wobbly]

I had a Schwannoma on my own toungue removed the year before last. It was an eyeball sized lump on my tongue. It hasn't grown back and I've had no problems since. It's one of the easier tumours to deal with - as your vet said - it's one very localised solid lump, so easier to remove it all without leaving any behind. Mine healed quickly with no problems, but it was in the mouth so to be expected. All in all, if I had to pick another tumour to suffer through, I'd choose a schwannoma again - it hasn't regrown, and no problems at all since removal.

When you come out of the anaesthetic though, it's excruciating because it's right on the nerve. I was in horrible pain when I woke up, they kept giving me more and more morphine, but the morphine seems ineffective for that kind of pain. Unable to talk because it was my tongue, I ended up frantically making writing gestures till they gave me pen so I could write down "local anaesthetic". They gave me a nerve block and it was fine after that - the local anaesthetic was far more effective than any other form of analgesic.

It would be worth asking your vet to give your dog a local anaesthetic at the surgery site when he comes round so he isn't in pain - the operation is right on a nerve - so the pain is much worse than for a regular operation.

Good luck - if my experience is any indication it'll be easy to remove it all, so no regrowth - all A-OK

Edited July 27, 2008 by Wobbly

[Charles Kuntz]

Hi, Charles Kuntz here. I am a specialist veterinary surgeon in Melbourne and subspecialty-trained in surgical oncology (cancer surgery). I published that largest collection of soft tissue sarcomas in dogs (including schwannomas). I am not "blowing my own horn" but just giving you my experience with these tumours. I have personally removed about 700 soft tissue sarcomas in dogs and cats.

Schwannomas are more correctly known as soft tissue sarcomas. Collectively, they are fairly common and account for 15% of skin and subcutaneous tumours in dogs. They uncommonly spread to other organs- lungs particularly (but not rarely) and commonly recur (in the same place). The best predictor of whether or not they will spread is the grade of the tumour. They are graded I,II and III. Grades I and II spread in about 10% of cases. Grade III tumours spread in 50% of cases. Chemotherapy has been shown definitely NOT to prevent spread.

The best predictor of recurrence of the tumour in the same site is the COMPLETENESS OF SURGICAL MARGINS. This relates to whether or not the surgeon got the whole thing out. They should be removed with 2 cm margins in all directions. Clean margins recur in 5% of cases in 5 years (A good surgeon gets clean margins in 95% of cases). Dirty margins recur in 75% of cases in 5 years. Radiation therapy is really effective at preventing recurrence in cases with dirty margins. (20% recurrence in 5 years with radiation compared to 75% recurrence without radiation). There are two facilities providing dedicated radiation therapy to animals in Australia.

These are highly curable tumours if treated appropriately and early.

Charles Kuntz