Solitary osteochondroma

Introduction to single osteochondroma Single osteochondroma is a kind of hamartoma of bone. It originates from subperiosteal hyperplasia of abnormal growth cartilage. It is a common benign bone tumor. It occurs in males, and the ratio of male to female is 1.5 to 2:1. In the growth phase of the bone, the slowly increasing painless callus is almost the only clinical symptom, and the correct diagnosis can be made by radiological imaging alone. The exact cause of its disease is unclear. Some people think that osteochondroma is a true tumor; others think it is lack of growth of developmental osteophytes. basic knowledge The proportion of illness: 0.002% Susceptible people: no specific people Mode of infection: non-infectious Complications: vascular injury

The cause of single osteochondroma

Causes:

Single osteochondroma is a kind of hamartoma of bone. It originates from subperiosteal hyperplasia of abnormal growth cartilage. It is a common benign bone tumor. The exact cause is still unclear.

Pathogenesis:

Gross examination: The size of osteochondroma can vary greatly. Osteochondroma, which is usually located in long tubular bone, has an average diameter of 4 cm. It is usually larger in flat bone or irregular bone. The largest individual report is 40 cm. The pedicled osteochondroma is tubular or conical, with a smooth or nodular surface, and its apical shape is different. The pedunculated osteochondroma is disc-shaped, hemispherical or cauliflower-like.

The top of the osteochondroma is covered with a cartilage cap, which changes with age. In a single osteochondroma of a child, the osteochondroma is mainly composed of cartilage, and its initial ossification merges with the edge of the new trabecular bone of the metaphysis. In childhood, the cartilage cap still covers the entire top of the osteochondroma. It is a white to bright blue hyaline cartilage similar to normal baby cartilage. Its thickness ranges from a few millimeters to 1 cm or more. With age, the thickness of the cartilage cap decreases. In many parts, the original cartilage cap often leaves a small amount of uneven residue, the thickness of which does not exceed a few millimeters. Does a single osteochondroma have malignant changes, and the thickness and shape of the cartilage cap Very important.

The tumor shows 3 layers of typical structure in the cut surface: 1 The surface layer is collagen connective tissue with rare blood vessels, which is connected with the surrounding periosteum and closely attached to the underlying tissue. The middle layer is gray-blue transparent cartilage, ie the cartilage cap, similar to Normal cartilage, usually a few millimeters thick, its thickness is related to the age of the patient. Children and adolescents are in the active period of bone growth, and the cartilage thickness can reach 3cm. Sometimes the cartilage cap is completely absent. This phenomenon is due to After stopping growth, the structure around the tumor causes pressure and wear on the cartilage cap. In adults, such as the cartilage cap, more than 1 cm thick, the possibility of malignant transformation of osteochondroma should be considered. The pedicled osteochondroma and the cartilage layer The area is large, and the 3 basal layer is the main body of the tumor, and the cancellous bone containing the yellow pulp is connected to the affected bone.

Microscopic examination: mainly to examine the cartilage cap of osteochondroma. The histological examination of the cartilage cap is similar to that of the epiphyseal growth plate. The following conditions can be seen: 1 In young patients, tumor growth is active, most of the binuclear chondrocytes are visible, 2 when the tumor When growth stops, the chondrocytes stop proliferating and degenerative changes occur. 3 When the cartilage layer is disturbed by growth, there may be calcareous clastic deposits in the cartilage. 4 When the tumor malignantly becomes chondrosarcoma, it is also significant. Calcification and ossification, and chondrocytes have atypical nuclei. In the growth phase of single osteochondroma, the appearance of the cartilage cap is the same as that of normal growth cartilage, but it is irregular. From the surface, hyperplasia, columnar, hypertrophy can be seen. And the calcified layer, and then the trabecular bone formed by the endochondral bone, its distribution, direction and shape are very irregular, occasionally containing cartilage islands, in adults, discontinuous and thin cartilage caps like mature hyaline cartilage, similar joints Cartilage. The only important thing in the histological examination of single osteochondroma is to confirm that there is no sarcoma in the cartilage.

Single osteochondroma prevention

There are no effective preventive measures for this disease, but it should be noted that although the function of the affected limb can quickly return to normal after surgery, early functional exercise is still necessary after the operation. Early functional exercise can prevent soft tissue adhesion and improve Efficacy.

Single osteochondroma complications Complications, vascular injury

The majority of osteochondromas have mild clinical signs and signs. A small number of patients can spontaneously absorb tumors in children and adolescents, and the tumors disappear. The reason is that some patients have osteochondroma fractures, and the tumors are absorbed due to active bone resorption. It is also possible that the tumor gradually merges into the enlarged metatarsal bone during growth and development, however, the following complications may also occur during development.

1. Fracture:

Uncommon, often occurs in large and pedicled osteochondroma, due to injury, but there is little delayed healing or non-healing, and individual patients disappear after fracture.

2. Bone deformity:

There are three bone malformations caused by osteochondroma: 1 poor bone tubularity, 2 widening of the metaphysis, 3 causing deformity of the surrounding bones, the latter often occurring in one of the two adjacent bones in which the osteochondroma is closely related. It is common for osteochondroma on the tibia to exert pressure on the tibia, causing humeral deformity.

3. Vascular injury:

Osteochondromas located near the knee joint can often cause vascular dislocation. More serious complications are motility, vein compression or pseudoaneurysm. This is a rare complication, but it has been reported that it is common in males and normal bones. The age at which the growth is nearly stopped, due to the loss of luster in the protective cartilage cap of the epiphysis, the blood vessels rub against the matte cartilage cap, the pulsation of the artery and the joint activity cause repeated damage to the vessel wall, and finally a pseudoaneurysm is formed. Almost all osteochondromas and pseudoaneurysms occur in the proximal end of the radial artery for two reasons: 1 the lower end of the femur and the upper end of the humerus are the most common parts, and the proximal end of the 2 iliac artery passes through the adductor It is fixed, and the distal end of this artery is also fixed by the branch of the anterior and posterior tibial artery. There is no activity at the distal end of the radial artery, so the bowel-like tension on the surface of the tumor is caused by the osteochondroma. An aneurysm is a pulsatile soft tissue mass, and the distal end artery pulsation may change, but the diagnosis depends on angiography.

4. Nerve damage:

This complication is rare and produces different types of clinical symptoms depending on the location of the disease.

5. Synovial cyst formation

A synovial cyst is formed around the top of the osteochondroma, which is generally osteochondroma, and has a large bone activity, such as the scapula and the distal femur.

6. Malignant changes

About 1% of patients have malignant changes, osteochondroma malignant changes can occur pain, swelling, soft tissue mass and other symptoms, X-ray can be seen on the original stable osteochondroma re-growth, bone destruction, calcification irregularities, etc. .

In some cases, the disease may be interlocked, and the osteochondroma may be fractured in the lower part of the femur, thereby damaging the surrounding blood vessels and forming a pseudoaneurysm of the radial artery. It is important to emphasize that if the disease is performed, if not Resection of the mass, including the normal pedicle or the surrounding bone tissue around the base and the bursa, may cause recurrence or adverse consequences of malignant tumors.

Single osteochondroma symptoms common symptoms bone pain, long bone swelling, pain, extra-bone mass

Most single osteochondromas are often found in children or adolescents, and about 70% to 80% of patients develop under 20 years of age.

1. Symptoms and signs:

There is no conscious pain, no tenderness, and the hard mass that grows up is its clinical feature. A slightly larger tumor sometimes shows a protrusion under the skin. When the tumor is too large, or because of the special anatomy, it can produce corresponding clinical symptoms and signs. Such as the tumor base fracture can cause pain and swelling.

2. Good hair parts:

Osteochondroma can be produced in bones with endogenous cartilage ossification. In long tubular bones, especially in the femur (30%), the tibia (20%), the tibia (17%) is the most common site of disease, and in some Some long tubular bones such as iliac crests and ulna are not common. The incidence of lower extremities is more than that of upper limbs. The ratio is 2:1. The typical pathogenesis of long tubular bone is in the sacral end, which rarely occurs in the backbone or epiphysis. Is another disease - Trevor disease, osteochondroma occurs in the rapid growth of long tubular bone, such as the distal femoral metaphysis, humerus, humerus, proximal metaphysis of the humerus.

The incidence of small bones in the hands and feet is about 10%, the humerus accounts for 5%, and the incidence of the spine is less (<2%). However, it is often caused by the compression of the spinal cord. On the spine, osteochondromas occur in the spine. Attachments, especially in the spinous processes, are common in the lumbar spine and cervical vertebrae. The incidence of osteochondroma in the scapula is about 4%. It is often located in front of the scapula. It can cause pain and bounce during exercise. It occurs in the osteochondroma of the scapula. When chest radiographs are sometimes misdiagnosed as intrapulmonary nodules.

Because single osteochondromas do not appear until they are quite large, they are rarely seen before 8 to 10 years old, and because their growth is similar to bones, their volume is maximized before and after puberty, so most singles Osteochondroma cases develop symptoms between the ages of 10 and 18, and are rare thereafter.

In the growth phase of the bone, the slowly increasing painless callus is almost the only symptom. The single osteochondroma originates from and is connected to the bone plane, but has no adhesion to the soft tissue. Some cases of single osteochondroma are Completely asymptomatic, can be found for imaging examinations for other reasons, single osteochondroma can be rubbed against the muscles covering the muscles, aponeurosis and tendon, forming a synovial cyst on its surface.

Almost 90% of single osteochondromas are located at the metaphysis of the long bones of the extremities, most commonly at the metatarsal ends of the knee (especially the distal femur) and the shoulder (proximal humerus), and the rest are the ankles. Proximal femur, wrist, single osteochondroma, less common in the trunk bone, and mainly found in the scapula, pelvis (mostly in the tibia), spine (back arch), individual cases found in the short tubular bone of the hands and feet, some Single osteochondromas located deep in the body, such as the vertebrae and tibia, can be found without symptoms.

Examination of single osteochondroma

Film degree exam

The imaging findings of this disease are very typical, and the correct diagnosis can be made by radiological imaging alone.

1. X-ray inspection:

The X-ray feature of osteochondroma is that there is a bony prominence on the surface of the long tubular bone, which is connected with the cognac and consists of the cortical bone and cancellous bone. Due to the different shape of the base of the tumor, it can often be divided into pedicles. There is a narrow stem with a wide top and no pedicle (the base is wide and flat). Osteochondroma often occurs at the attachment of the metaphyseal tendon ligament, and its growth often follows the direction of the force generated by the tendon and ligament. The metaphyseal end grows to the backbone of the same bone. There is cartilage covering at the top of the tumor. It is called the cartilage cap. The thickness is different. The thin one is only a linear transparent area, which is difficult to see. The thick one is a dense pattern of cauliflower. If the cap is small, the boundary is clear, with regular point calcification, this performance is benign growth. If the cap is large and thick, the boundary is unclear, and there is irregular or incomplete calcification, it should be noted that it may be malignant. .

Osteochondroma is often large at the site of the humerus. It can form a large soft tissue mass and can displace the surrounding structure. The type of calcification is diverse and often irregular. Benign or malignant changes are difficult.

Osteochondroma has similar X-ray findings in the hand and small bones in the long tubular bone. It is worth noting that there is a small osteochondroma in the fingertips, called the inferior epiphysis.

2. Bone scan:

Bone scans are mostly positive in active osteochondroma in childhood and weakly positive or negative in adult inactive osteochondroma.

3. Other imaging technologies:

For most single osteochondromas, X-ray examination can meet the needs of diagnosis and treatment, but for more complex anatomical parts, such as scapula, pelvis, spine, etc., CT examination is often needed to help the bone of long tubular bone. For chondromas, CT examination can provide a relationship between the tumor and the affected bone, the type of lesion matrix, calcification, and the thickness of the cartilage cap, which can be helpful in the differential diagnosis of osteochondroma or perichonal chondrosarcoma.

Diagnosis and diagnosis of single osteochondroma

According to the history, age, clinical manifestations, predilection sites, X-ray examination, more can be clearly diagnosed.

Because of its typical imaging performance, the disease can be diagnosed only by clinical and imaging basis. The only problem is the need to identify benign osteochondroma and osteochondroma with sarcoma. It is necessary to comprehensively analyze all clinical and radiological images. , bone scan, gross pathology and histology.

Sometimes it is necessary to distinguish between calcification (ossification) and para-osteoma of the tendon.

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