Osteochondroma is a benign tumor–like formation, which is a bony protrusion, covered from the outside with a cap of cartilage tissue, and filled from the inside with bone marrow contents. It is usually found in the metaphysical region of long tubular bones, as the bone grows, it shifts closer to its middle part. Tumor-like formations of small size are not accompanied by any symptoms. Large osteochondromes can cause pain and limb dysfunction. Pathology is diagnosed on the basis of examination data and X-ray examination. Treatment is only surgical. The prognosis is favorable.
D16 Benign neoplasm of bones and articular cartilage
Osteochondroma it is called a benign formation, which is a defect that occurred during the development of the bone. It is usually located on long tubular bones near the joints, but as the child grows, it shifts towards the diaphysis. Less commonly found on the ribs, pelvic bones, shoulder blade, vertebrae and articular bones of the clavicle. As a rule, the disease is asymptomatic, but when it reaches a large size, it can cause pain syndrome and cause a number of complications.
Osteochondroma is the most common benign lesion of the skeleton, accounting for about 20% of the total number of primary bone tumors. It is usually detected at the age of 10-25 years. At the end of the growth of the skeleton, the growth of education also stops more often, however, exceptions are described.
The reasons for the occurrence of single formations have not been fully clarified. Many specialists in the field of traumatology and orthopedics believe that this is a bone malformation that grows in parallel with the bones of the skeleton. In addition, there are radiation osteochondromes, which are formed in patients who received radiation therapy in childhood. Such neoplasias are usually multiple, found in 12% of patients exposed to radiation at a dose of 1000-6000 rad. and they can form not only in long tubular bones, but also in the bones of the pelvis and spine.
And finally, another reason for the formation of multiple osteochondromas is osteochondromatosis (another name is multiple exostatic chondrodysplasia). This disease is hereditary, is transmitted by an autosomal dominant type and is detected in young people under the age of 20 years.
Osteochondroma is a dense tumor–like formation with a shiny and smooth surface. In its structure, it simultaneously resembles the diaphyseal and articular parts of a normal bone. There is a cartilaginous cap on top, covered with a thin fibrous layer. The thickness of the cap can reach 1 mm. In children, this cap is thicker. As it grows, it becomes thinner, and in adulthood it may be absent or represent a very thin plate.
Under the cartilage there is a compact bone tissue, under it there is a spongy bone. In the center there is a bone marrow substance associated with the bone marrow channel of the “mother” bone. In the mass of spongy bone, there are areas of osteoid, decayed cartilage and amorphous masses. In some cases, a bag is formed over the bone tumor, filled with decayed cartilaginous corpuscles or “rice corpuscles”, as well as fibrin deposits. The size of osteochondroma can vary significantly and in most cases ranges from 2 to 12 cm. At the same time, formations of a larger diameter are also described in the literature.
There are typical locations of osteochondroma localization. Thus, in 50% of patients, these tumor-like formations are found in the distal end of the femur, as well as in the proximal parts of the tibia and humerus. In other cases, all other parts of the skeleton may be affected, with the exception of the bones of the facial skull – osteochondroma never occurs in this area. Relatively rarely, damage to the bones of the feet, hands and spine is detected.
Tumors of small size are asymptomatic and become a random find when the patient feels a “bump” on the bone. A large osteochondroma can squeeze muscles, tendons and nerves. In such cases, patients turn to doctors because of pain or impaired limb function. Another reason for the development of pain syndrome may be a bag forming over the affected area. In some cases, the reason for seeking medical help is a fracture, spontaneous infarction in the affected area or rare complications of osteochondroma – a false popliteal artery aneurysm and popliteal vein thrombosis.
Palpation reveals a dense, immobile, painless formation. The skin above it is not changed and has a normal temperature. When a bag is formed over a solid tumor, another, softer and more mobile formation can be felt.
The diagnosis is made on the basis of a combination of clinical and radiological signs. At the same time, radiography usually plays a decisive role in making a final diagnosis. Sometimes magnetic resonance imaging and computed tomography are also used as additional research methods.
Radiographs reveal a change in the contours of the bone due to the presence of a tumor-like formation associated with the main bone with a wide and thick leg. The superficial parts of the formation have uneven contours and may resemble cauliflower in shape. In some cases, the leg is missing, and the osteochondroma is adjacent to the “mother” bone. The contours of the osteochondroma are clear, continuous, directly passing into the contours of the main bone.
The cartilaginous cap on X-rays is usually not determined, except in cases when there are foci of calcification in it. Therefore, we should not forget that the actual diameter of the osteochondroma may be 1-2 cm larger than the diameter determined by radiography.
If an increase in the size of the cartilaginous cap is suspected, magnetic resonance imaging is necessary. Diagnosis usually does not cause difficulties, but in some cases the disease may need to be differentiated with osteoma, paraosteal osteosarcoma, paraosteal bone-cartilage proliferation and chondrosarcoma resulting from osteochondroma malignancy.
Traumatologists-orthopedists are usually engaged in treatment. The only therapeutic technique is surgical removal of tumor–like formation within healthy tissues. Indications for the removal of both single and multiple formations are impaired limb function, pronounced skeletal deformity, as well as rapid tumor growth. If there are no indications for surgical treatment, it is necessary to monitor the patient and periodically repeat the X-ray examination to assess the dynamics of the process (presence or absence of growth, change in structure). The operation is performed under general anesthesia in a hospital setting. The doctor makes an incision over the affected area and performs an edge resection, removing the tumor along with the base of the leg. Bone grafting is not required.
Prognosis and prevention
The prognosis is favorable, especially in the case of single formations. After surgical treatment, a stable recovery occurs. Malignancy of single osteochondromes is observed in 1-2% of patients. With multiple formations, the risk of malignancy increases to 5-10%. Unfavorable in prognostic terms are an increase in the thickness of the cartilaginous cap of more than 1 cm, an increase in the diameter of the osteochondroma of more than 5 cm and a sudden rapid growth of tumor-like formation, therefore, in all these cases, surgical treatment is offered to patients. Preventive measures have not been developed.
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