Non-ossifying fibrous tumors 4 cm large do not require treatment if they do not have any symptoms. If the tumor is expanding, or if it is more serious, surgery is needed. Anaplastic fibroma is a common tumor in children, located in the long bones, preferably in the thigh bone and calf bone. Since non-ossifying fibroma has the tendency of self-healing, those who found non-ossifying fibroma 4cm in size without clinical symptoms do not need to be treated and can be observed regularly. If the tumor is found to be expanding within a short period of time, or symptoms such as obvious pain, activity limitation, or a tendency to fracture, it should be timely to seek medical treatment for surgical treatment, and bone grafting by scraping off the lesion can be chosen, with a better prognosis. The examination found that there is a 4 cm large non-ossifying fibroma, you need to take into account their own situation, to determine whether the surgical treatment. If surgery is needed, you should go to a regular hospital and cooperate with the doctor for standardized treatment. If you don’t take surgery, you need to keep a good mood and go to the doctor for regular checkups.