Fibromas are classified in a spectrum from fibromas to fibrosarcomas according to the number of mitosis they include. Malignant fibrosarcomas which have aggressive pattern show higher mitotic activity and nuclear atypia. Cellular fibromas with less than 4 mitotic figures under 10 high power fields (HPF) are benign. "Mitotically active cellular fibromas" that are classified between the cellular fibromas and fibrosarcomas, have ≥4 mitotic figures in 10 HPF but do not have nuclear atypia. A very few cases of mitotically active cellular fibromas have been reported in the literature. In this report, we present the case of mitotically active cellular fibroma in a patient who applied to our clinic with the complaint of pelvic mass.
Keywords: Mitosis; cellular fibroma; pelvic mass.