Bone cyst
Introduction
Introduction to bone cyst Bone cyst is a benign lesion of bone, also known as solitary bone cyst, simple bone cyst (simplebonecyst), the wall of the capsule is a fibrous envelope, and the capsule is yellow or brown liquid. Bone cysts occur in the metaphyseal end of the long bone and the medullary cavity of the backbone. It is rare in the vertebral body, mainly based on surgical treatment, and the prognosis is good. Occurs in 4-20 years old, more common in children aged 5-15. Occurs in the femoral neck, the upper end of the femur and the upper end of the tibia. As you age, the cyst gradually moves toward the backbone. basic knowledge The proportion of the disease: the incidence of this disease is about 0.005% - 0.009% Susceptible people: no specific population Mode of infection: non-infectious Complications: fracture
Cause
Cause of bone cyst
Blood stasis (30%):
Bone cyst is a benign lesion, and the cause is not yet clear. Some scholars believe that the bone cyst is caused by obstruction of the endovascular end of the bone and blood stasis.
Abnormal bone development (20%):
Some scholars believe that bone cyst disease is a kind of tumor, degenerative change of inflammation tissue, its growth, metabolic obstruction results or related to bone dysplasia.
Trauma (20%):
Some scholars believe that it is possible to form a localized cyst in traumatic hemorrhage, and then locally absorb ossification.
Prevention
Bone cyst prevention
The current cause of the disease is not yet clear, and there are no effective preventive measures. Therefore, early detection, early diagnosis and early treatment are the key to the prevention and treatment of this disease.
Complication
Bone cyst complications Complications
The most common complication of bone cysts is pathological fracture. When the bone cyst is accompanied by pathological fracture, the fracture piece is displaced into the capsule cavity due to fluid outflow in the capsule. This sign is called fragmentation trap and is Reynolds. Proposed by the family.
Symptom
Symptoms of bone cysts Common symptoms Joint pain Bone cysts Joint swelling Tendon cysts Neck pain Children repeated fractures
1. Occurs in 4-20 years old, more common in children aged 5-15 years, occurs in the femoral neck, the upper end of the femur and the upper end of the tibia. As the age increases, the cyst gradually moves toward the backbone.
2. Generally no obvious symptoms, most of them due to pathological fractures, pain, swelling, dysfunction and treatment, X-ray film only found the disease.
3. X-ray film shows that the long bones of the metaphysis or the backbone have elliptical osteolytic destruction, the boundary is clear, and a thin layer of hardening zone can be seen around it, and the cortical bone can be slightly expanded and thinned.
Examine
Bone cyst examination
Bone cyst is a tumor-like bone disease of unknown cause. It has no clinical symptoms in the clinic. It is found after X-ray examination after pathological fracture. The auxiliary examination methods are as follows:
1. Pathological examination: In pathology, the cyst size is more than 3~10 cm, which is round or elliptical at the metaphyseal end of the long bone, and some columnar is consistent with the long axis of the backbone. The cyst contains brownish yellow. A clear liquid or bloody liquid, which is composed of the same serum as the inner wall covered with a thin, smooth fibrous connective tissue membrane.
2, X-ray examination: X-ray film is mainly characterized by expansive bone destruction, located in the center of the medullary cavity, surrounded by a thin layer of hardened ring.
3, CT examination: CT showed a circular or elliptical low-density foci in the center of the bone marrow cavity, the water sample density, cystic expansion, even the density of the lesion was slightly higher, suggesting that there may be bleeding.
4. MRI examination: MRI is typical, the lesion boundary is usually smooth, and the signal intensity is completely dependent on the protein content in the liquid. Generally, the cyst fluid has a very uniform low signal on T1WI and a very uniform high signal on T2WI. The lower the protein content, the closer the signal intensity is to water, and the higher the protein content is slightly above water on T1WI and slightly below water on T2WI.
Diagnosis
Diagnosis and differentiation of bone cyst
diagnosis
1. More common in children and adolescents, occurs in the long bones.
2. No obvious symptoms, or mild pain and tenderness, pathological fractures may be the earliest symptoms and signs, or lesions found by X-ray.
3. X-ray film shows that there is a transparent shadow with uniform elliptical density at the end of the long bone. The lesion is limited, and there is a clear boundary between the bone and the normal bone. The cortical bone is expanded and thinned.
4. Pathological examination can confirm the diagnosis.
Differential diagnosis
The disease is similar to the image of bone fiber dysplasia, and the identification is more difficult. There are mainly the following identification points:
1. Clinical manifestations:
The clinical symptoms of dysplasia of bone fibers are localized bulging or swelling, pain, deformity, and slow progression of the disease. Patients with bone cysts generally have no obvious symptoms, or only have dull pain, are intermittent, or have pain after exercise.
2, bone fiber abnormal proliferation and bone cyst lesion morphology and internal structure:
Most of the bone cysts are oval and have a uniform density inside the capsule; while the abnormality of the bone fibers is diverse in morphology and internal structure, which can be divided into phagocytic, cystic, ground glass, loofah, and hardening.
3. Dislocation of bone fragments during pathological fractures:
When the bone cyst is accompanied by pathological fracture, the bone fragments are displaced into the cyst cavity. When the pathological fracture of bone fiber abnormal proliferation occurs, the bone fragments are not significantly displaced, and the formation of osteophytes is less, and it is easy to form nonunion.
4. Location:
When the bone cyst occurs at the metaphysis, it does not exceed the epiphyseal plate; and the abnormal proliferation of bone fibers involving the epiphysis often crosses the tarsal plate, and the adjacent cognac has an image of dysplasia of the bone fiber.
In addition, the disease needs to be differentiated from giant cell tumor of bone, eosinophilic granuloma and aneurysmal bone cyst.
