Correct spelling for the English word "fibromvitis" is [fˌɪbɹəmvˈa͡ɪtɪs], [fˌɪbɹəmvˈaɪtɪs], [f_ˌɪ_b_ɹ_ə_m_v_ˈaɪ_t_ɪ_s] (IPA phonetic alphabet).
Fibromvositis.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
There is no specific word fibromvitis in common usage or in medical terminology. It is possible that you might be referring to fibromyalgia, a chronic disorder characterized by widespread musculoskeletal pain, fatigue, and tenderness in localized areas. However, the etymology of fibromyalgia comes from the Latin word fibro meaning fibrous tissue, myo meaning muscle, and algos meaning pain. Therefore, fibromyalgia essentially means muscle and connective tissue pain.