I am a male and do have a spinal tumour (probably harmless, gets checked regularly). A chance finding whilst excluding ankylosing spondylitis via MRI, ending in the fibromyalgia diagnosis.
So that's the nearest anyone'll get to a "fibromyalgia tumour" - it can't be that, as there's no such thing, as said, but was found during the diagnostic process, but will have been there before fibro.
For getting the severe disability status the tumour wasn't even considered slightly, because it isn't disabling. Fibromyalgia was only considered "10%", because it per se is not disabling, altho mine is very much so. So I got it cos of my seizures, which are hardly disabling...
Another form of disability, similar to PIP in the UK, is based on how I can work, which is close to nil, so I score "as high as I need". But this also has nothing to do with the tumour, and not really with the labels of my diagnoses, but with the decline of my energy due to fibro plus now MCAS.