Abnormal bone fiber proliferation disease is a self-limiting, slowly progressive benign bone fiber tissue disease of unknown etiology, also known as osteofibrous dysplasia. I. Etiology: The etiology of this disease is unknown. It may be related to trauma, infection, endocrine dysfunction or some causes of local blood circulation disorders, but none of them have been confirmed. It is generally accepted that the disease is not a true tumor. It stops developing in most cases after developmental maturity. The disease occurs mostly before the age of 20 years, occasionally in infants and elderly people over 70 years old. The incidence is 1:2 in both sexes. Clinical manifestations: The main manifestations are deformation and swelling of the diseased bone area, and those occurring in the face show expansion and deformation of the affected jaws, narrowing of the nasal cavity, loosening or displacement of the teeth, deformation of the alveolar ridge, lacrimation, and elevation of the palate. Headache and epistaxis may occur as the lesion progresses. If the lesion occurs in the temporal bone, it often shows volume expansion and deformation of the temporal bone, narrowing of the external auditory canal, and conductive deafness. The disease may invade the sinuses, orbit and skull base extensively, and has a tendency to grow malignantly, manifesting as nasal congestion, hyposmia, facial asymmetry, eye protrusion, displacement, diplopia, visual impairment, or even blindness, and difficulty in opening the mouth. Those involving the skull base are prone to malignant transformation. Imaging examination has special significance for the diagnosis of this disease. Diagnosis: This disease can be diagnosed without histological evidence by combining history, location, physical signs and imaging examination. Treatment: The disease is mainly surgical resection, because radiotherapy may induce malignant changes. It is best to wait until the disease is stable before surgery. However, if the lesion develops faster, accompanied by obvious deformities and dysfunction, surgery should be performed as soon as possible. Although radical excision is the best treatment, it can lead to functional impairment and cosmetic defects. Conservative partial excision is the best option, but there is a possibility of recurrence after surgery. Intraoperative bleeding may be high, and blood should be prepared preoperatively if necessary. Surgical excision should be done aesthetically to achieve as much symmetry in the facial appearance as possible.