Chondrosarcoma is a malignant tumor of the skeleton originating from cartilage tissue. It can develop on unchanged bones or be formed as a result of the degeneration of some benign tumors. It is manifested by progressive pain and swelling in the affected area. In some cases, there is a local increase in temperature, expansion of the network of subcutaneous veins over the tumor area and restriction of movement in the nearby joint. Several variants of the course are possible – from relatively favorable, with slow growth and late metastasis to unfavorable, with rapid growth and early appearance of metastases. Pathology is diagnosed by the results of radiography, CT, MRI. Surgical treatment – bone resection, amputation or exarticulation.
Chondrosarcoma is the second most common malignant neoplasm of the skeleton. According to various data, it makes up from 7 to 16% of the total number of malignant bone tumors. Surgical treatment is a radical operation in which the neoplasm is removed together with the surrounding tissues. In about 60% of cases, the disease is detected in middle-aged and elderly patients (40-60 years old). However, people of all ages can suffer from this disease. The earliest appearance of the tumor was noted at the age of 6 years, at the latest – at the age of 90 years. In men, chondrosarcoma is found 1.5-2 times more often than in women.
The causes of the neoplasm have not been clarified. Neoplasia can develop initially or be detected with the malignancy of a number of dysplastic processes. It is possible to damage any bone structures, but pelvic bones, shoulder girdle bones, ribs, shoulder and thigh bones are more often affected.
Taking into account the origin, all chondrosarcomas are divided into primary and secondary. Primary, in turn, are divided into central (growing inside the bone) and periosteal or peripheral (growing on the outer surface of the bone). Among the secondary chondrosarcomas, tumors that have arisen as a result of malignancy of chondromes, chondromixoid fibroids, chondroblastomas, bone-cartilage exostoses or tumors with bone chondromatosis (Ollier-Maffuchi disease) are distinguished. Primary chondrosarcomas are detected in 90% of cases, secondary – 10% of cases.
Depending on the features of the structure, typical, light-cell, anaplastic and undifferentiated chondrosarcomas are distinguished. In addition, there is a classification of the degree of malignancy of chondrosarcoma, taking into account the features of the tumor identified during histological examination:
- 1 degree. The intercellular substance mainly consists of chondroid tissue, in which chondrocytes with dense small nuclei are located. There are few multinucleated cells, and there are no mitosis figures.
- 2 degree. The intercellular substance is more often myxoid, there are more cells than at grade 1 malignancy, there are clusters of cells along the periphery of the lobules. The nuclei are enlarged, single figures of mitosis are revealed. There are zones of destruction (necrosis).
- 3 degree. The intercellular substance is myxoid. Cells are located in the intercellular substance in groups or strands. A large number of irregular or star-shaped cells are detected. There are many multinucleated cells and cells with enlarged nuclei. Mitosis figures are observed. There are extensive necrotic foci.
The higher the degree of malignancy of chondrosarcoma, the greater the likelihood of early metastasis and recurrence during surgical removal of the tumor.
The clinical picture depends on the type and degree of differentiation of tumor cells. With highly differentiated chondrosarcoma, the disease can develop over several years. As a rule, this course is observed in patients aged 30 years and older. When studying the medical history, it turns out that the patient was disturbed for a long time first by unpleasant sensations, and then by weak, slowly progressing pains in the affected area. The pain syndrome could worsen at night, weakened under the influence of painkillers, but did not disappear after rest.
The tumor can reach a significant size, cause a visually visible deformation or be determined by palpation. In some cases, there is also an increase in skin temperature and dilation of subcutaneous veins over the area of chondrosarcoma, although these symptoms are not as pronounced as in other malignant bone tumors. Sometimes there is a restriction of movement in the nearby joint.
With low-differentiated forms of chondrosarcoma, a more violent course is observed. As a rule, no more than 1-3 months pass before the patient goes to the doctors. The main complaint, as in the previous case, is pain at the site of the lesion, sometimes increasing at night and not disappearing after rest. However, with low-grade forms of the tumor, pain is more resistant to the action of analgesics.
The pain syndrome is characterized by constancy and is rapidly increasing. The swelling also increases faster than with a relatively favorable course option. An increase in local temperature, restriction of movements in a nearby joint and dilation of subcutaneous veins occur with the same frequency as in highly differentiated tumors. Low-grade forms of chondrosarcoma occur more often in young and adolescent age and are characterized by a higher frequency of relapses.
With all types of large-sized chondrosarcomas located in the pelvic bones, a number of characteristic symptoms may be observed due to the pressure of the tumor on neighboring organs and tissues. With compression of the sciatic plexus, there are pains that radiate to the buttock and along the back of the thigh. With compression of the neck of the bladder, difficulties in urination are possible. With compression of the iliac vein, unilateral edema of the lower limb on the side of the lesion may develop.
Distant metastases occur more often with low-grade forms of chondrosarcoma. Malignant cells enter other organs with blood flow (hematogenically). Usually the regional lymph nodes, liver, lungs and brain are affected. Periosteal chondrosarcomas are characterized by a special type of metastasis. Around such tumors there is a reactive zone – the area separating the neoplasm from the surrounding tissues. Peripheral chondrosarcomas germinate this zone and form so–called jumping metastases (satellite nodes) – foci of malignant cells that have no direct connection with the main tumor. Such foci are located either in the most reactive zone, or near it in the thickness of healthy tissues.
The diagnosis of the disease is carried out by oncologists, to whom patients are usually referred by traumatologists and orthopedists. Clinical symptoms of chondrosarcoma are nonspecific, so the diagnosis is made on the basis of additional studies. With central chondrosarcomas, an irregularly shaped, indistinct focus of destruction is found on X-rays, usually located in the metadiaphysis. Sometimes the tumor looks speckled due to small foci of calcification. The bone around the hearth is swollen.
In peripheral chondrosarcomas, radiographs reveal a contrast formation of a bumpy shape with fuzzy contours located on the outer surface of the bone. In the transition zone between normal bone and altered tumor tissue, uneven compaction is noted. The cortical layer of bone in this area is uneven. As with central chondrosarcoma, mottling may be detected due to calcification sites.
To clarify the diagnosis, a bone trepanobiopsy is performed. The material is taken from several tumor sites. In the process of histological examination, the degree of malignancy of chondrosarcoma is determined. As a rule, these studies are sufficient for an accurate diagnosis. In some cases, additional methods may be needed: bone MRI, computed tomography and osteoscintigraphy. Chest x-ray is prescribed to detect lung metastases in patients with chondrosarcoma.
Patients are hospitalized in the oncology department. Most chondrosarcomas are resistant to chemotherapy and radiation therapy, so the main method of treatment for this disease is surgery. With chondrosarcomas of grade 1 and 2 malignancy, the neoplasm is removed. The chondrosarcoma is excised in a single block together with the tissues of the reactive zone and some reserve of surrounding healthy tissues so that there are no tumor cells left in the wound. Depending on the size and localization of the tumor, either resection of a part of the bone is performed, or its removal with subsequent endoprosthetics.
With chondrosarcomas of grade 3 malignancy, radical surgical intervention may be required – amputation or exarticulation of the affected limb. If, due to general contraindications or the inaccessibility of the tumor, its surgical removal is impossible, chemo and radiation therapy is performed. However, these methods are only palliative, aimed at slowing the growth of chondrosarcoma, and do not provide a cure.
Prognosis and prevention
The prognosis for chondrosarcomas is always serious. The outcome depends on the degree of neoplasia malignancy. At grade 1, the five–year survival rate is 90%, at grade 2 – 45-60%, at grade 3 – about 30%. Preventive measures have not been developed.
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