hi - fibromyalgia normally does not create tumors some people with fibromyalgia have Lipomas that are fat tumors but are just under the skin fibromyalgia is not spin related it is brain related. so not too sure what your condition is.
Ah, now I think I realize this may be a confusion of terms, I think something like "(solitary) fibrous tumour" or "neurofibromatosis". Both usually benign, but can go malignant. Nothing to do with fibromyalgia.