What Causes Fever While Suffering From Neurofibromatosis?

Is it normal for someone with neurofibromatosis to have a fever accompanied by pain? My sister was in so much pain in hospital, doctors were checking to see what was the cause of her pain. What they found is that she has 3 ovarian cysts that are benign but they stop her menstrual period and fill up in her stomach. My sister also has a tumor on her face accompanied by fever. She is currently taking Apo-Naproxen and Novo-Gesic Forte. I am worried about her because her gynecologist doesn t think it is serious. She is going to be seen by her gynecologist in October. Should I be very worried that maybe this is not neurofibromatosis because her test results prove negative but doctors are convinced she has it based on her symptoms.