Fibrous dysplasia of bone

Introduction to osteofibrousosis Fibrous heterogeneous hyperplasia, also known as poor fibrous structure, is characterized by fibrous tissue hyperplasia and metaplasia through bone formation, and the formed bone is a naive interwoven bone. Another type of lesion is the formation of lamellar trabeculae at the same time as fibrous tissue hyperplasia, and osteoblasts on the surface of the trabecular bone. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific population Mode of infection: non-infectious Complications: fracture

Cause of osteomyergic hyperplasia

(1) Causes of the disease

The cause is unknown.

(two) pathogenesis

1. Gross specimen characteristics: The periosteum of the fibrous specimens has no change, the cortex is thinner, and sometimes it can be cut with a scalpel. The profile is pale and dense tissue, which has a certain sense of elastic sand. The gritty is mainly due to the soft and brittleness in the fibrous tissue. The bone-like tissue trabecular component, and varies with the number of trabeculae and the degree of maturity, this tissue is not rich in blood vessels, however, especially in the cancellous bone (the humerus, ribs, pelvis, metaphysis), Many blood vessel sections can be seen, sometimes there are cystic cavities, edema or hemorrhagic tissue with bloody fluids; sometimes, especially single bone type, the entire osteolytic area contains liquid components, which are easily confused with bone cysts, and sometimes have cartilage island structures in tissues. It is more common in children and cognac.

2. Histopathological features: Histopathology of fibrosis has a bundled tissue between the small trabecular structures, ie, fibroblasts, and no osteoblasts are arranged around the trabecular bone.

In general, in a thin collagen fiber network, tissue-rich fibroblasts are abundant, and division is relatively rare. Sometimes, they are arranged in a spoke-like shape, sometimes containing multinucleated giant cells, mainly in areas rich in blood vessels or bleeding (especially in blood vessels). Osteoporosis, such as ribs, some regional tissue cell fibroids replace trabecular bone, and some are replaced by mucoid tissue.

The bone-like tissue and the trabecular bone are generally sparse, rarely coarse, and there are no osteoblasts arranged around. The trabecular bone of the fibrous heterogeneous proliferation is generally a textile structure and cannot form a lamellar bone.

In the tissue of fibrosis, the blood vessels are rare, and some cystic areas are rich in capillaries and bloody exudation.

Sometimes, the cartilage tissue area is visible in the tissue between the poorly constructed fibrous bone tissues. The cartilage has small localized nodules and normal hyaline cartilage structures. The tissue characteristics of these cartilage areas are different from those of isolated or multiple chondromas. Similar to the growth of the tarsal plate or the proliferative cartilage of the repaired epiphysis, the histological discontinuity between the cartilage area and the poorly constructed fibrous bone tissue, the author denied that the cartilage is the result of tissue birth, in most cases In the onset of children or adolescents, the cartilage area is visible. These patients have not been operated or fractured. The cartilage seems to originate from the tarsal plate. In other cases, the subperiosteal cartilage may be due to recent pathological fractures, minor fractures, and surgery. After treatment, the result of repairing osteochondral callus is produced.

Histological performance is the same as imaging and general performance, and varies with the patient's age.

Osteofibrosis prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Complications of osteofibrosis Complications

2/3 cases can be complicated by pathological fractures. Unlike simple traumatic fractures, the bones of pathological fractures are previously eroded, destroyed, hollowed out by certain diseases, and then encounter a slight external force, and even no external force can spontaneously fracture due to their own gravity. Therefore, when the fracture occurs, if the external force causing the fracture is very slight, there is pain in the site before the fracture or a fracture occurs in the same place or other parts in the past, the possibility of pathological fracture should be alert.

Symptoms of osteomyergic hyperplasia Common symptoms Vaginal bleeding Intelligence reduces eyeball precocious puberty

The ratio of male to female is 1.1:1, the incidence is mostly around 10 years old, but the treatment is often in adolescence, and the endocrine disorder is 3-4 years old, even after birth, the incidence rate in China is 10/million~ 30/million, accounting for the first place in bone tumor-like lesions, 2/3 to 3/million in foreign countries. Osteofibrosis can occur in any bone, and single limb lesions are often located in the proximal bone. It can be localized or spread to the diaphysis, often in the femur, humerus, humerus and pelvis, often on one side of the limb, bilaterally affected, and asymmetrical, the upper limbs are often seen in the skull at the same time, the lesion of the trunk can spread to several Ribs and vertebral bodies and their attachments, the ribs are often not limited to one side, the limbs of the fibrous fibrosis are mainly on one side, the lower limbs, and only the individual bones on the opposite side can also affect the skull, ribs or pelvis at the same time. .

The most common symptom is bone damage. The severity of the symptoms is related to age, duration and damage. The younger the age, the more severe the symptoms. Most early cases can be asymptomatic for many years, followed by pain and dysfunction. For arch deformities or pathological fractures, as many as two-thirds of cases have reported pathological fractures, and nearly half have multiple fractures. Some cases have this as the first symptom, which is characterized by frequent mild trauma as a cause. The fracture is painful, swollen, dysfunctional, but rarely displaced. Most of them can heal after braking. The superficial bone lesions often have deformities or masses, such as facial asymmetry, upper palate, similar to lion faces. Sometimes causing eyeballs, ribs and vertebrae, when the chest is asymmetrical, localized protrusions, long bones of the extremities are inflated and deformed, the metacarpal bone is invaded, the extremities are uplifted, and deep lesions are generally difficult to detect early. .

Skin pigmentation is also a common sign. It is characterized by scattered waist, hips, thighs, etc., on the affected side and bounded by the midline. It is a spot-like or flaky dark yellow or yellow-brown skin spot, sometimes very shallow, not The ridges are dentate, irregular, and of varying sizes, but the tissue structure is similar to normal skin.

Sexual precocity only occurs in a few cases with severely damaged bones. Most of them are female. Females show vaginal bleeding, but not menstruation. In severe cases, they appear in 3 to 4 months. Second sexual characteristics appear earlier and vulva. Larger, early breast development, premature pubic hair and pubic hair, occasional mental decline and other endocrine symptoms, extensive multi-bone lesions, skin pigmentation and precocious puberty, known as McCanne-Albright syndrome.

Examination of bone fibrosis

X-ray examination, single-mode fibrous heterogeneous lesions in the medullary cavity, the metaphyseal or diaphysis of the long tubular bone, central or eccentric, the X-ray of the lesion appears as a blurred intramedullary radiotransparent (low density) Area, often described as "matte glass", which can be seen in irregular bone texture, bones have different degrees of expansion, cortical bone thinning, the boundary between the lesion and normal bone is obvious, you can see the reactive hardening margin Band, no periosteal reaction, lesions in the femoral neck or the upper end of the femur can be sickle-shaped deformation, described as "Shepherd's stick" deformity, the lesion boundary of the spine is also clear, expansion, X-ray has a low-density area, the interior is separated Or streaky, can collapse due to pathological fractures, localized lesions only occur in the metaphysis, such as the proximal metaphysis of the femur, extensive lesions often invade the end of the long bone and most of the backbone, the bone is prominent outward. The cortical bone is thick and uneven, or bent to one side. If it occurs in the humeral shaft, the periosteum produces new bone after pathological fracture, which makes the cortical bone thicken and harden. The lesion rarely invades the epiphyseal cartilage. After epiphyseal closure line, only invade the bone end.

Multi-mode fibrous heterogeneous hyperplasia lesions often invade the number of bones, and there are violations of adjacent bones, such as invasion of the ipsilateral humerus, femur, tibia and fibula, the lesion of the tibia is osteolytic, showing a larger polycystic Shape, which can be seen in bone texture, with varying degrees of bone swell, lesions of long bones of the extremities often involve all of the bone, the width of the medullary cavity is uneven, the cortical bone is thinned and expanded at the widening, and the texture inside the medullary cavity disappears, being frosted. Glassy, some parts of the bone are highly swelled, and there are cystic manifestations, pathological fractures often occur. In skull lesions, the skull base is dense, the pillow and the humerus are deformed, and the shadow is dense and loose.

Hand bones are rarely invaded alone, often in the upper limbs, affecting the hand bones, X-ray films showing diffuse expansion of the metacarpal and phalanx (sometimes length), this change can affect the metacarpal callus and carpal bone.

The imaging manifestations of fibrosis have changed in adolescents and adults at different times. The lesions develop slowly and stop expanding. The walls and cortex of the osteolytic area gradually thicken. Sometimes, the density of the ground glass area increases until the ivory density increases. .

The X-ray manifestations of malignant transformation of fibrosis are dependent to some extent on the histological type of the lesion. The boundaries of the osteolytic range in the lesion are unclear, and the cortical bone defect and adjacent soft tissue blocks are suggestive of malignancy.

Diagnosis and differentiation of bone fibrosis

According to medical history, clinical manifestations and X-ray signs, the diagnosis of typical bone fibrosis is not difficult.

Single patients should be differentiated from solitary bone cysts, isolated endogenous chondromas and giant cell tumors. Multiple patients should be differentiated from hyperparathyroidism.

1. Solitary bone cyst: The disease occurs mostly in people under 20 years old. The lesion begins in the vicinity of the backbone and the epiphysis, and then the bone grows gradually toward the backbone, showing a central symmetry expansion. Transparency is more obvious; the general specimen is a single-shell bone shell, very thin, with incomplete osteophytes, a grayish white or reddish-brown fiber membrane on the bone wall, the content is a transparent liquid; the endometrium is fibrous connective tissue The blood vessels are rich, and the old ones may have granulation, blood clots, calcification points, and sometimes bone-like tissues or trabecular bones.

2. Isolated endogenous chondroma: Endogenous chondroma is common in the foot, multiple lesions of the hand and small bone, common arc on the X-ray film, irregular calcification of the ring and the semi-circle, and the profile is a hard and shiny light blue-white tissue. There is ossified tissue or mucin-like tissue, and the mirror is a lobulated vitreous cartilage with calcified or fibrous ossified tissue.

3. Giant cell tumor of bone: Most of the tumor is a single lesion, located at the end of the bone, showing obvious swelling, simple osteolytic changes, no obvious hardening ring around, the cross section sees the bone cavity is mostly eccentric, full of dark red or Yellow fragile tissue and scattered old blood, mirrored as a rich network of blood vessels, filled with uniform shape of spindle cells and scattered multinucleated cells.

4. Hyperparathyroidism: This disease can cause extensive bone changes, obvious deformity, systemic bone decalcification, no bone regeneration or sclerosis, the main pathological changes are bone resorption and fibrous scar formation, which has bleeding phenomenon. There are also fine bone-like tissue and trabecular bone formation, increased serum calcium, decreased serum phosphorus, and increased calcium and phosphorus in the urine.

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