Fibrous dysplasia

Introduction to bone fiber dysplasia Fibrousdysplasia is a self-limiting benign bone fibrous tissue disease with unknown etiology and slow progression. Normal bone tissue is absorbed, and replaced with fibrous tissue of homogenous spindle cells and dysplastic reticular trabecular bone, which may be stagnation of reticular bone immature bone maturity, and reticular bone support disorder after birth. Or caused by poor interstitial differentiation of bone, the disease is not uncommon, accounting for about 25% of all bone new organisms, accounting for 7% of all benign bone tumors, about 70% of single bone type, multi-bone type without endocrine Disorders accounted for about 30%, and multi-bone type with endocrine disruptors accounted for about 3%. basic knowledge The proportion of illness: 0.005% Susceptible people: friends in children and youth, women are more common Mode of infection: non-infectious Complications: eyeballs, brain atrophy

Causes of bone fiber dysplasia

Blood circulation disorder (20%):

The cause of this disease is unknown, may be related to trauma, infection, endocrine dysfunction or some causes of local blood circulation disorders, but have not been confirmed, it is generally believed that this disease is not a true tumor, and some believe that it begins with endocrine and metabolic dysfunction .

Tissue hyperplasia (30%):

At present, most scholars believe that the abnormality of bone fiber is caused by abnormal development of primitive mesenchymal tissue and abnormal proliferation of fibrous tissue in bone.

Pathological change

The vascular supply varies greatly. The lesion tissue is generally white, grayish white or pale yellow. It is slightly softer than normal bone tissue. It has a sandy or elastic feeling when cutting. The huge bone damage mostly erodes and expands from the bone marrow. Tubular bone and flat The bone cortex of the bone only leaves two thin shells, and the outer shell is removed, such as decapsulation. Under the microscope, the size, shape and distribution of the trabecular bone are different, and are irregularly embedded in the loose or dense enrichment. In the connective tissue of cells and blood vessels, this tissue is similar to the result of connective tissue metaplasia. The trabecular bone morphological variation is large, mostly spherical, curved in the transverse section, C-shaped or arched, irregular edge, bone cell cavity Wide, trabecular bones are closely arranged to form a bone mesh. The trabecular bone is composed of the original bone of the crude fiber. It is mesh-like rather than plate-shaped under polarized light. Occasionally, the reticular bone plate is deformed, sometimes seeing the arched bone. The trabeculae surround a cardiovascular system, and most trabecular bones lack the contours of osteoblasts, which can be distinguished from ossifying fibroids.

Prevention of bone fiber abnormal proliferation

The current cause of bone fiber abnormal proliferation is unknown, and there is no effective preventive measure. Therefore, early diagnosis and treatment of this disease is the key to the prevention and treatment of this disease.

Complications of bone fiber dysplasia Complications, eyeball, brain atrophy

The disease can be widely invaded into the sinus, eyelids and anterior cranial fossa, clinically a malignant growth tendency, manifested as nasal congestion, olfactory sensation, facial asymmetry, ocular protrusion, displacement, diplopia, visual impairment and difficulty in opening the mouth, etc. Abnormal proliferation of bone fibers in the sphenoid sinus area, and more severe pain in the frontal or occipital area.

Because the sphenoid sinus wall is thin, the lesion is easy to expand to the surrounding structure, involving II, III, IV, V, VI and other cranial nerves to produce symptoms and signs of cranial nerve damage. Those with larger lesions can cause brain atrophy or produce high intracranial pressure. disease.

Symptoms of bone fiber dysplasia Common symptoms Eyeballs, nasal congestion, visual acuity, muscle fiber size, eyeball displacement, diplopia, tear, external auditory canal, sinus, nasal conduction, deafness

About 60% of the disease occurs before the age of 20, occasionally in infants and the elderly over 70 years old, the incidence of men and women is 1:2; more than 80% of the symptoms of the bone area deformity swelling.

Due to the different parts of the primary site and the extent of involvement, the corresponding clinical symptoms can be manifested. The facial features are asymmetrical on both sides, the eyeball is displaced, the protrusion is narrow, the nasal cavity is narrow, the teeth are loose, the alveolar ridge is deformed, the tears are formed, and the ankle is raised. As the lesion progresses, headaches and occasional nasal discharge can occur.

If it occurs in the tibia, it often shows swelling and deformation of the tibia, narrow external auditory canal, and conductive deafness. There are stenosis of the external auditory canal, about 16% with cholesteatoma, cholesteatoma, often lead to temporomandibular arthritis, facial paralysis, labyrinthitis or intracranial complications, lesions involving the cochlea and internal auditory can produce sensorineural deafness, The rock bone is invaded, and it is prone to symptoms of involvement in the middle cranial fossa or posterior fossa.

The disease can be widely invaded into the sinuses, eyelids and anterior cranial fossa, clinically a malignant growth tendency, manifested as nasal congestion, olfactory sensation, facial asymmetry, eyeball protrusion, displacement, diplopia, visual impairment and difficulty in opening the mouth, etc. Abnormal proliferation of bone fibers in the sphenoid sinus area, more severe pain in the frontal or occipital area. Because the sphenoid sinus wall is thin, the lesion is easy to expand to the surrounding structure, involving the cranial nerves of II, III, IV, V, VI and so on. Symptoms and signs of nerve damage, larger lesions can cause brain atrophy or high intracranial pressure.

Examination of abnormal bone fiber proliferation

Image examination has special significance for the diagnosis of this disease.

According to X-ray findings, the disease is divided into three types:

1 deformed osteitis type: often manifested as multi-bone lesions, characterized by thickening of the skull, unilateral blistering of the outer and parietal bones of the skull, osseointegration of the intraplate to the stenosis and cranial cavity, thickening of the skull Common limitations and diffuse ray-transparent and dense areas coexist. This bone resorption and hardening coexist very much like the manifestation of Paget deformity osteitis. The skull enlarges and hardens and can expand from the frontal bone to the occipital bone. Facial involvement can lead to sputum and nasal cavity. The stenosis and sinus cavity disappeared, accounting for about 56% of this type.

2 hardening type: this type of more common maxillary hypertrophy, can cause uneven alignment of teeth, nasal cavity, sinus pressure is reduced, the maxilla is more affected than the mandible, and mostly single bone type, the damage is hardened or frosted glass appearance, on the contrary, Mandibular lesions are more common in multiple bone types, which show that the isolated bone wall is smooth and permeable to radiation, which accounts for about 23%.

3 capsule type: the skull is isolated or multiple ring or rosette-shaped defect, the defect begins from the thin hardening edge, its diameter can reach several centimeters, the isolated damage has eosinophilic granuloma, and the multiple defects can be mistaken as Hand Schüller Christian. Disease, occasionally several types of X-ray appear on the same individual, this type accounts for about 21%, using CT or MRI examination, can determine the location and extent of the lesion, and can show the connection with soft tissue, regular inspection can dynamically observe the lesion The degree of development is important for selecting surgical approaches, reducing complications and estimating prognosis.

Diagnosis and differentiation of bone fiber abnormal proliferation

diagnosis:

This disease is not easy to find in the early stage of single bone. It is usually combined with medical history, location, signs and imaging examinations. It can be confirmed without histological evidence.

Differential diagnosis

1. ossifying fibroma: It has been clarified in recent years that the disease and bone fiber dysplasia are two completely different diseases. The former is clinically slow-growing, isolated damage, invading the mandible more than the maxilla, occasionally in the frontal bone and The ethmoid bone is more than the male, and it occurs in the 15 to 26 years old. The X-ray has a clear outline and a large and transparent appearance. The center is spotted or opaque. Under the microscope, the fibrous component of the fibrous bone is mainly irregular. The trabecular bone is disorderly distributed in the fibrous matrix and constitutes the center of the reticular bone, but has osteoblasts at the periphery of the slab bone and at the occlusal margin.

2. Eosinophilic granuloma: a benign isolated non-neoplastic osteolytic lesion, originated from the reticuloendothelial system, common in the frontal bone, parietal bone and mandible, mostly before the age of 30, mostly male, in histology, It consists of dense foam tissue cells with different numbers of eosinophils and multinucleated giant cells. The tissue nucleus contains small vesicles. Eosinophils contain small vacuoles. The giant cells are Langhan type and foreign body type. These cells are stove-shaped. Sexual agglomeration.

3. Gardner syndrome: This syndrome is a multiple osteoma that invades the upper and lower jaw, the skull and occasionally on the long bone, accompanied by thickening of intestinal polyps, dermoid cysts, fibroids and long cortical corrugated cortical bone.

4. Giant dental bone tumor: usually involving the mandible, can cause the cortical bone to enlarge, X-ray examination shows a dense blocky body, often originated from heredity, no source of infection was found in histology.

5. Exogenous osteoma: malignant tumors and cysts of the paranasal sinuses should be identified to prevent misdiagnosis.

6. Multi-bone bone fiber abnormal proliferation, should also be differentiated from hyperthyroidism, paget disease, neurofibromatosis and jaw hypertrophy.

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