fibrous dysplasia of the skull
Introduction
Introduction to skull fibrosis Skull fiber dysplasia is a disease in which fibrous tissue replaces bone and causes thickening and deformation of the skull. The lesion can only affect the skull, but it can also affect the bones in other parts of the body. basic knowledge The proportion of illness: 0.025% Susceptible people: no specific population Mode of infection: non-infectious Complications: deafness
Cause
Causes of abnormal cranial fibrosis
(1) Causes of the disease
The cause of this disease is unknown. Most people think that abnormal dysplasia of bone fibers is a genetic disorder. However, some people think that it is related to inflammation or dysfunction of blood vessels, nutritional nerves, endocrine, etc., and some people think that it is abnormal with bone interstitial. Growth-related, the relationship between craniocerebral trauma and abnormal fibrosis of the skull has yet to be further explored in the future.
(two) pathogenesis
The main pathological changes of cranial fibrous dysplasia are fibrous tissue hyperplasia in the medullary cavity. The enlargement of the medullary cavity makes the cortical bone thin and has no periosteal reaction. The bone of patients with abnormal sclerosing fibrosis is treated by osteoclasts. Instead, there are immature trabecular bone and fibrous interstitial, the shape and size of the trabecular bone are extremely inconsistent, some are "U" or "V" type, and the interstitial fibers are mainly spindle cells, which are cystic. Arrangement, collagen formation, cartilage tissue is less common, if a large number of cartilage tissue is found, it may be converted to chondrosarcoma, but malignant changes are rare, lesions occur in the frontal bone, parietal bone, humerus and sphenoid bone, The skull base is more common. Adult patients often invade the sphenoid bone, leading to stenosis of the optic canal and compression of the optic nerve. The bone of the lesion is soft and hard rubbery. It contains grit-like ossified islands, often with small cysts. Hemorrhage area, but no systemic osteoporosis and calcium, phosphorus metabolism disorder, lesions on the surface of the skull increased in the small tube hole, the bone section is red, a little diffuse oozing, the bone grinding specimens see the trabecular bone is thin, mesh Outer plate, baffle plate and the inner panel no obvious boundaries, into one of the three, i.e., barrier plate structure similar to, but different from the normal barrier plate structure.
Prevention
Cranial fiber dysplasia prevention
The cause of this disease is unknown. Most people think that abnormal dysplasia of bone fibers is a genetic disorder. However, some people think that it is related to inflammation or dysfunction of blood vessels, nutritional nerves, endocrine, etc., and some people think that it is abnormal with bone interstitial. Growth related. Therefore, the disease can not be prevented. Regular physical examination is recommended, so early detection and early treatment are important for preventing this disease.
Complication
Skull fiber dysplasia complications Complications
If surgery is performed, the following complications may occur:
1. Postoperative visual acuity is related to intraoperative operation touching the optic nerve, and can gradually recover.
2. In the cerebrospinal fluid rhinorrhea, when the bone flap is removed or the thickened bone is removed, the frontal sinus or ethmoid sinus is opened, and the sinus is not repaired during the operation. If it is not cured or cured after several weeks of conservative treatment, it will recur. Need to be re-surgically repaired.
Symptom
Skull fiber abnormal hyperplasia symptoms common symptoms deafness intracranial pressure increased eyelid reduction precocious hardening
Skull fiber dysplasia is more common in adolescents, but also in adults. It is more common in women, and each skull can be involved. In clinical cases, the lesions invade the frontal bone, the parietal bone and the tibia, especially the skull base. Most patients can Without any clinical symptoms, individual patients may have mild headaches. The most common clinical manifestations are changes in the shape of the head and face and asymmetrical protrusions on the skull. The ridges are soft and hard rubbery, with sand-like ossification. In Xiaodao, the vast majority of skulls with degenerative thickening develop extracranial and do not grow into the brain. Therefore, there is little clinical manifestation of brain compression and increased intracranial pressure. Clinically, single lesions or lesions are limited. In one part, it is more common to invade several adjacent skulls. In recent years, reports of multiple lesions simultaneously invading bones in other parts of the body are not uncommon. The lesions can only invade the calvaria and cause local deformities of the skull. It can invade the skull base and have corresponding clinical manifestations. For example, the lesion invades the bone around the orbital anterior fossa, which can lead to eyelid contraction, eyeball protrusion, and limited eye movement; Invasion and maxillary bones, hyperplasia of the maxilla, causing facial swelling, "bone lion face" may occur; lesions invading the saddle region and sphenoid sinus, can cause optic nerve hole stenosis, optic nerve compression and atrophy, patients can appear Progressive vision loss, or even blindness; lesions invade the pituitary, some endocrine symptoms, such as precocious puberty, occur in the tibia, which can cause stenosis of the external auditory canal, leading to conductive deafness, lesions occurring outside the skull Common in the bones of the spine and lower limbs, which can be fractured due to similar pathological changes.
Examine
Examination of abnormality of skull fibrosis
Mild or moderate elevation of alkaline phosphatase in blood has a reference value for the diagnosis of sham fibrosis.
X-ray examination has diagnostic value for the diagnosis of sham fibrosis. The cranial plain film is mainly a circular or round-shaped translucent area in the cranial stenosis, and the skull base lesion is characterized by dense and thick bone. Normal bone is replaced by fibrous tissue, and there is bone hyperplasia and cartilage residue, so its performance can be varied and can be roughly divided into three types:
1. Cyst type is more common in the early stage of the disease or lesions in the calvarial area. Between the skull barriers, cyst-like bone density reduction areas of different sizes can be seen, some of which are multi-atrial, widened, and raised. Thinning, while the inner panel is often unaffected.
2. The sclerotic type is more common in the late stage of the disease or in the lesion at the base of the skull. The lesions are extensive, often causing changes in the skull deformity, thickening of the bone, and the increase in the shadow density is an "ivory" hardening change, which is more common in the frontal plate. And the winglet part of the sphenoid bone.
3. The mixed type is cystic and sclerotic at the same time, more common in the skull, and the smaller one needs to be differentiated from the skull changes caused by meningiomas. If it is multiple, bones can be seen in other parts of the body. The above-mentioned similar performance, when there is cartilage tissue, is cloud-like or cotton-like shadow, and when the bone tissue is more, it can be ground glass.
Diagnosis
Diagnosis and differentiation of abnormality of skull fiber
diagnosis
According to the age of onset, location and other clinical manifestations, especially in combination with the characteristics of the skull X-ray, diagnosis can be made.
Differential diagnosis
1. Meningiomas: Skull changes in sclerosing cranial fiber dysplasia on X-ray films are similar to changes in skull caused by meningioma, so it needs to be differentiated. The characteristics of bone changes caused by meningioma are: inside the skull, Both the outer plate and the dysplasia are hyperplasia, and the local bone sclerosis is whitened. In addition, the CT scan of the head is easier to distinguish between the two. The meningioma is characterized by an intracranial close to the hardened skull and a clear high density. In the lesion, the lesion was uniformly enhanced, but the skull fibrosis was not manifested.
2. Osteosarcoma: the most common skull tumor, mostly occurs in young people aged 20 to 30 years old, a few are also seen in children or the elderly, the course of disease is longer, the smaller tumors generally have no symptoms, the larger ones may have Slight pain or numbness, X-ray manifestations are limited, round or elliptical, uniform bone density increase area, some cases can be blurred boundary bone density reduction area, inner and outer plates are involved at the same time to occur In the frontal bone, the parietal bone is more common, while the humerus and skull base are less common, and most of them develop in the extracranial direction. Therefore, there are few symptoms of brain pressure and increased intracranial pressure. According to the age, location and X-ray Features are easier to distinguish than the two.
3. Eosinophilic granuloma: occurs in children and young people around 20 years old, more common in men, mostly in the frontal bone, parietal bone, often manifested in a short period of time (generally no more than 1 month) suddenly There is a head painful mass, the local lymph nodes do not increase, but the patient has fatigue, low fever, much like mild suppurative osteomyelitis, local bone destruction can be seen on the skull X-ray film, there may be thickened bone reaction around, blood image There are eosinophilia, according to the above characteristics can be identified.
4. Malformation osteitis: Paget disease, the disease is more common in adults after middle age, more men than women, often family tendencies, lesions can also involve the skull and other bone tissue, the early manifestations of skull lesions often appear as tablets The osteolytic changes of the shape have obvious X-ray translucent areas on the X-ray film. Later, there is extensive skull hyperplasia, and the most obvious is the slab and the outer plate. In most cases, the trabecular bone can be seen. The blood supply of the area is particularly rich, and some lesions have a tendency to become sarcoma. According to the age, history and skull X-ray findings, the vast majority of patients can make differential diagnosis. Some patients with difficult identification can only be identified by biopsy. diagnosis.
