Osteofibrodysplasia is a self-limited benign fibrous tissue disease with unknown etiology and slow progress. Normal bone tissue is absorbed and replaced by fibrous tissue of homogeneous spindle cells and trabecular meshwork dysplasia, which may be caused by immature bone maturity of reticular bone, disorder of reticular bone support after birth or poor differentiation of interstitial tissue that constitutes bone. This disease is not uncommon in clinic, accounting for about 25% of all bone tumors and 7% of all benign bone tumors. Single bone type accounts for about 70%, bone type without endocrine disorder accounts for about 30%, and bone type with endocrine disorder accounts for about 3%.
diagnose
It is not easy to find the disease in the early stage, but it can be diagnosed without histological evidence by combining the history, location, signs and imaging examination.
Treatment measures
This disease, especially the single bone type, is mainly surgical resection, because radiotherapy may induce malignant transformation. In view of the slow clinical progress of this disease, patients with mild or asymptomatic lesions can temporarily not undergo surgery, but should be closely followed up. Patients with rapid lesion development, obvious deformity and dysfunction should be used as surgical indications. Radical resection is the best treatment, but it has the disadvantages of dysfunction and cosmetic defects. Conservative partial resection is easy to recur, in which the single bone type is 2 1% and the multi-bone type can be as high as 36%. The choice of surgical method and approach should be flexibly mastered according to the primary site, invasion range and degree of functional damage. In principle, the diseased tissue should be removed as thoroughly as possible, and the physiological function and cosmetic effect of the organ should be preserved to the maximum extent.
Oral intubation general anesthesia should be used for children and patients with extensive lesions during operation. Patients with limited lesions can also be removed under local anesthesia.
There are many kinds of surgical incisions, which can be selected and applied according to the pathological changes. (1)① Cowell-Luc method: It is suitable for patients whose lesions widely involve maxilla, nasal cavity, suborbital wall, ethmoid sinus and sphenoid sinus; ② Weber-Ferguson method: It is suitable for patients with extensive invasion of maxilla, infraorbital wall, zygomatic bone, hard palate and sphenoethmoid sinus. ③ Combined craniofacial approach: including double frontal flap or single frontal flap +Weber-Fergusson incision, which is suitable for a wide range of lesions that originate at the base of anterior cranial fossa or sinus and orbital wall and invade each other. ④Fish method: It is suitable for patients whose lesions mainly involve temporal bone, external auditory canal, middle ear, inner ear, petrous bone and middle cranial fossa.
It is best to cut it several times with a flat chisel, a round chisel or a large curette. There is a lot of oozing blood on the wound. Bone wax should be used to stop bleeding and necessary blood transfusion should be carried out during the operation, especially in children.
Surgical resection of this disease has a good prognosis, so the important neurovascular lesions at the skull base and adjacent to the skull should not be excessively removed during the operation to avoid accidents.
etiology
Unknown. It may be related to some reasons such as trauma, infection, endocrine dysfunction or local blood circulation disorder, but it has not been confirmed. It is generally believed that this disease is not a real tumor.
pathological change
The vascular supply changes greatly, and the diseased tissue is generally white, grayish white or yellowish, which is slightly softer than normal bone tissue. I feel sandy or elastic when cutting, and most of the huge bone damage comes from bone marrow erosion and expansion. There are only two thin shells left in the cortex of tubular bone and flat bone. Remove the shells, such as removing capsules. Microscopically, trabecular meshwork varies in size, shape and distribution, and is irregularly embedded in loose or dense connective tissue rich in cells and blood vessels. This tissue is similar to the result of connective tissue metaplasia. The shape of trabecular bone changes greatly, and its cross section is mostly spherical, arc, C-shaped or bow-shaped, with irregular edges and wide lacunae of bone cells. Bone trabeculae are closely arranged to form a bone network. Trabecular bone is composed of coarse fibrous protobone, which is reticular rather than tabular under polarization microscope. Occasionally, the reticular bone plate is deformed, and sometimes the arcuate trabecular bone surrounds a cardiovascular system. Most trabecular bones lack the outline of osteoblasts. It can be differentiated from ossifying fibroma.
clinical picture
Clinical classification Most authors agree with the classification proposed by Beleval and Schneider( 1954), that is, there are three types of the disease: ① single bone type: single or multiple lesions involving one bone, of which maxilla is the most common, accounting for 64%, mandible for 36% and craniofacial bone for 10%. ② Bone type without endocrine disorder: multiple injuries involving multiple bones. The incidence of craniofacial bone involvement is 5% in moderate bone involvement and 100% in extensive bone involvement. After reviewing 144 patients reported in the literature, Van Tilburg found that the frontal bone and sphenoid bone were the most involved, followed by ethmoid bone and temporal bone. It can be unilateral or bilateral. ③ Bony type with endocrine disorder: the ratio of this type to single bone type is 30∶ 1. Skin lesions are scattered in many bones, often distributed unilaterally, accompanied by large skin pigmentation spots. More common in women, showing precocious secondary sexual characteristics.
Clinically, about 60% of the disease occurs before the age of 20, and it is occasionally seen in infants and the elderly over 70 years old. The incidence of male and female is 1∶2. More than 80% of the patients showed abnormal swelling of the diseased bone area, and those who occurred in the face showed bilateral asymmetry, prominent eyeball displacement, nasal stenosis, loose teeth, abnormal alveolar ridge, tearing and palatal uplift. With the development of the disease, headaches and occasional nosebleeds may occur. Because of the different primary site and involved range, it can show corresponding clinical symptoms. If it occurs in the temporal bone, it often shows swelling and deformation of the temporal bone, stenosis of the external auditory canal and conductive deafness. About 16% patients with external auditory canal stenosis are complicated with cholesteatoma. Cholesteatoma often leads to temporomandibular arthritis, facial paralysis, labyrinthitis or intracranial complications. Lesions involving cochlea and internal auditory canal can produce sensorineural deafness. When the petrous bone is invaded, the symptoms of middle cranial fossa or posterior cranial fossa are easy to appear. The disease can widely invade sinus, orbit and anterior cranial fossa, and has a malignant growth tendency in clinic, which is manifested as nasal congestion, hypoesthesia, facial asymmetry, exophthalmos, displacement, diplopia, visual impairment, and difficulty in opening mouth. Abnormal hyperplasia of bone fibers in sphenoid bone and sphenoid sinus area, and more severe pain in forehead or pillow. Due to the thin wall of sphenoid sinus, the lesion is easy to spread to the surrounding structures, involving II, III, IV, V, VI and other cranial spirits, resulting in symptoms and signs of cranial nerve damage. Large lesions can lead to brain atrophy or intracranial hypertension.
accessory examination
Imaging examination has special significance for the diagnosis of this disease. According to the X-ray findings, the disease can be divided into three types: ① Osteopathy type: it is often a bone lesion, characterized by skull thickening, unilateral bubble expansion of the outer plate and parietal bone of the skull, swelling of the inner plate to the plate barrier and cranial cavity, and coexistence of localized and diffuse transparent areas and dense areas in the thickened skull. The absorption and hardening of this kind of bone is very similar to the manifestation of paget's osteitis deformans. The skull becomes bigger and harder from the frontal bone to the occipital bone. Facial involvement can lead to orbital nasal stenosis and sinus cavity disappearance, accounting for about 56%. ② Sclerosing type: This type is more common in maxillary hypertrophy, which can lead to irregular tooth arrangement and reduce the compression of nasal cavity and paranasal sinuses. Maxillary involvement is more than mandible, and most of them are single bone type. The damage has a hardened or frosted glass appearance. On the contrary, mandible injury is more common in bone type, which shows that the isolated bone wall is smooth and transparent to radiation. This type accounts for about 23%. ③ Cystic type: The skull presents isolated or multiple annular or rose-shaped defects, which start from the thin hardened edge and can reach several centimeters in diameter. Isolated disease becomes eosinophilic granuloma, multiple defects can be misdiagnosed as Hand Schüller Christian disease, and occasionally several X-ray types appear in the same individual. This type accounts for about 2 1%. Using CT or MRI examination, the location and scope of the lesion can be clearly defined, and the connection with soft tissue can be displayed. Regular examination can dynamically observe the development degree of lesions, which is very important for selecting surgical approach, reducing complications and estimating prognosis.
differential diagnosis
In the process of diagnosis, we should pay attention to distinguish it from the following diseases:
1. In recent years, it has been proved that ossifying fibroma and fibrous dysplasia of bone are two completely different diseases. The former grows slowly in clinic and is an isolated lesion, which invades mandible more than maxilla and occasionally appears in frontal bone and ethmoid bone. Women are more than men, and most of them occur in 15 ~ 26 years old. X-ray shows clear outline, enlarged and transparent appearance, and punctate or opaque center. Microscopically, fibrous bone is dominant, and irregular trabeculae are randomly distributed in the fibrous matrix, forming the center of reticular bone, but osteoblasts are formed around the plate bone and occlusal edge.
2. Eosinophilic granuloma is a benign and isolated non-neoplastic osteolytic lesion, which originated from the reticuloendothelial system. Common in frontal bone, parietal bone and mandible. Most of them are before the age of 30, and most of them are men. Histologically, it consists of dense foam cells with different numbers of eosinophils and multinucleated giant cells. The nuclei of tissues contain vesicles, eosinophils contain tiny vacuoles, and giant cells are Langerhans type and foreign body type. These cells are clustered together.
3. Gardner syndrome This syndrome is multiple osteomas, which invade the maxilla, mandible and skull, and occasionally invade the long bone, accompanied by intestinal polyps, dermoid cysts, fibromas and local corrugated cortical thickening of the long bone.
4. Huge cementoma usually involves the whole mandible, which can cause the expansion of cortical bone. X-ray examination showed dense massive accumulation. Often originated from heredity, and no source of infection was found in histology.
5. It should be differentiated from exogenous osteoma, malignant tumor of paranasal sinus and cyst to prevent misdiagnosis.
6. Osteofibrodysplasia should be differentiated from hyperthyroidism, paget's disease, neurofibromatosis and jaw obesity.