Bone cyst

Introduction Bone cyst is a tumor-like lesion of the bone, also known as solitary bone cyst, simple bone cyst (simplebonecyst). The wall of the capsule is a fibrous envelope with a yellow or brown liquid inside the capsule. Mainly based on surgical treatment, the prognosis is good. The exact cause of the bone cyst is unknown, and there are many theories. Mirra speculates that a small number of synovial cells with secretory function in the embryonic period will fall into the bone, resulting in the accumulation of synovial fluid and the formation of a bone cyst. Bone cysts rarely show symptoms during their development. Most patients are found to have localized swelling, swelling, tenderness, inability to move and other fractures due to traumatic pathological fractures. A few cases showed local mass or bone thickening, joint activity was normal, and muscles were slightly atrophied. Patients who occur in the lower extremities, occasionally limp.

Cause

The cause is not yet clear. Some scholars believe that bone cysts are caused by obstruction of blood vessels at the end of the bone and blood stasis. It is also believed that this disease is a degenerative change of certain tumors and inflammatory tissues, and the results of growth and metabolism inhibition are related to bone dysplasia. It is also thought that it is possible to form a localized cyst in the traumatic hemorrhage, and then locally absorb the ossification.

an examination

Related inspection

CT examination spiral CT examination of bone three-phase imaging

1. 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.

2. Generally no obvious symptoms, most of them due to pathological fractures, pain, swelling, dysfunction and treatment, X-ray film found the disease.

3. X-ray film shows that the long bone or the backbone has elliptical osteolytic destruction, the boundary is clear, and a thin layer of hardening zone can be seen around it. The cortical bone can be slightly expanded and thinned.

Differential diagnosis

Differential diagnosis of bone cysts:

Aneurysmal bone cyst

Both have similarities in clinical and X-rays, but aneurysmal bone cysts are mostly eccentric, moderately erosive, and often can be worn to break the cortical bone, the edges of which are blurred, and the insects The shape of the sacral cortex often expands like a balloon, which can puncture fresh blood, and often has a blood pulsation when puncture. The bone cyst is a yellow or brown liquid.

2. Giant cell tumor of bone

More common in adult patients over the age of 20, occurs in the distal end of the femur and proximal humerus, the lesion is multi-cavity or foamy, highly eccentric and expansive, with a certain degree of erosion, can penetrate the cortical involvement Features such as bones. However, giant cell tumors of the upper end of the femur and bone cysts are sometimes difficult to identify.

3. Single bone fibrosis

The two are sometimes very similar in clinical and X-ray findings, especially when the fibrous heterogeneous hyperplasia has no hairy vitreous or loofah-like changes and only cystic swelling changes, it is difficult to identify, but the extent of lesions in fibrosis is more Extensive, not necessarily central growth, in addition to the bone end, often invaded the metaphysis and the backbone.

4. Isolated bone eosinophilic granuloma

The disease lesions are often small, can occur in any part of the bone, but the backbone is more, often accompanied by obvious pain, white blood cell count and eosinophil count can be increased, X-ray image lesion edge is not as good The bone cyst is clear and has a periosteal reaction.

5. Non-ossifying fibroma

Mostly eccentric, often a certain distance from the tarsal plate, the lesion range is small.

6. Endogenous chondroma

It occurs in the short bone of the hand and foot, and there are calcified spots in the transparent area of the lesion on the X-ray film.

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