Ewing sarcoma is a malignant neoplasm that develops from bone tissue. It occurs more often in adolescence or adolescence. Affects flat and long tubular bones. It is one of the most aggressive tumors, prone to early metastasis. It is manifested by pain, then by edema, local hyperemia and hyperthermia, as well as local expansion of the venous network. In the later stages, a tumor is determined, often a pathological fracture of the affected bone occurs. Combined treatment includes surgery (if possible, radical removal of the neoplasm) in combination with radiation therapy, as well as pre– and postoperative chemotherapy.
ICD 10
C40 C41
Meaning
Ewing sarcoma is a malignant bone tumor characterized by rapid growth and early appearance of metastases. It usually develops in children, adolescents and young people. It is accompanied by pain and local changes in soft tissues (edema, hyperemia, hyperthermia). In the later stages, the tumor becomes noticeable during examination and palpation. Treatment is carried out by an oncologist, includes surgical removal of the neoplasm, chemo and radiation therapy.
Ewing sarcoma is the second most common malignant tumor of bone tissue that occurs in childhood, accounting for 10 to 15% of the total number of malignant neoplasms of bones. It is rare in adults over 30 and children under 5 years of age. The greatest number of cases of the disease occurs at the age of 10 to 15 years. Boys get sick more often than girls, Caucasians – more often than representatives of the Negroid and Mongoloid race.
In some cases, the primary neoplasm in this disease occurs in soft tissues, and not in bones. This form of the disease is called extraossal (extraosseous) Ewing’s sarcoma. In addition, there are aggressive malignant tumors similar in nature and structure, belonging to the group of so-called tumors of the Ewing sarcoma family. In this group, in addition to extraosseous and bony sarcomas, PNEO (peripheral primitive neuroectodermal tumors) are included. Extraosseous forms and PNEO together account for about 15% of the total number of cases of Ewing’s sarcoma.
Ewing sarcoma causes
The causes of Ewing’s sarcoma are currently not precisely established. However, a number of researchers in the field of modern oncology believe that hereditary predisposition plays a certain role in the occurrence of this disease. In about 40% of cases, a connection with a previous injury is revealed. There are data indicating an increased likelihood of developing the disease in patients with certain types of skeletal abnormalities (aneurysmal bone cyst, enchondroma, etc.), as well as disorders of the intrauterine development of the genitourinary system (renal reduplication, hypospadias). No connection with the effects of ionizing radiation has been established.
Pathanatomy
Most often, Ewing sarcoma is detected in the femur, pelvic bones, tibia and fibula, scapula, ribs, humerus and vertebrae. When it occurs in long tubular bones, the tumor is usually localized in the diaphysis area, and then, as it grows, it spreads towards the epiphyses. In more than 90% of cases, there is an intramedullary location of the neoplasm and a tendency for the spread of tumor cells along the bone marrow canal.
Ewing’s sarcoma most often metastasizes to the lungs. In second place in prevalence are metastases to the bone marrow and bone tissue. In the late stages, metastases to the central nervous system are detected in almost all patients. In rare cases, distant metastases to the pleura, mediastinal lymph nodes, internal organs and retroperitoneal space are detected. Due to early metastasis, by the time of diagnosis, from 15 to 50% of patients already have metastases, which can be detected using routine studies. The overwhelming number of patients have micrometastases.
Ewing sarcoma symptoms
The first, earliest sign of the disease is pain in the affected area. At first it is weak or moderate, spontaneously weakens or disappears, and then appears again. Unlike pain in inflammatory processes, such pain does not weaken at rest, at night or when fixing a limb. On the contrary, Ewing sarcoma is characterized by increased pain at night.
As the pain progresses, it becomes more intense, deprives sleep and limits daily activity. Pain contracture develops in the nearby joint. Palpation of the affected area is painful. The skin temperature above it is elevated. There is pasty soft tissue, local hyperemia and dilation of subcutaneous veins. The tumor increases rapidly and (usually a few months after the onset of the first symptoms) becomes so large that it can be probed. In the later stages, a pathological fracture often occurs in the area of neoplasm.
Local clinical signs are combined with increasing symptoms of general tumor intoxication. Patients complain of weakness and loss of appetite. There is a decrease in weight up to exhaustion. Body temperature is elevated to subfebrile or even febrile figures. Regional lymphadenitis is determined. According to blood tests, anemia is detected.
Some symptoms depend on the localization of the neoplasm. So, when Ewing sarcoma occurs, lameness appears on the bones of the lower extremities. If the vertebrae are affected, it is possible to develop compression-ischemic myelopathy with impaired pelvic organ function and paraplegia phenomena. With neoplasms in the area of the chest bones, respiratory failure, pleural effusion and hemoptysis may occur.
Diagnostics
As a rule, at the initial stage, patients turn to traumatologists. And the first study that makes it possible to suspect Ewing’s sarcoma is an X-ray of the affected bone. This pathological process is characterized by a combination of reactive and destructive bone formation processes. The contours of the cortical layer are indistinct, delamination and de-fibration of the cortical plate is determined.
When the periosteum is involved in the process, small lamellar or needle formations are detected on the radiograph. In addition, the images show an area of soft tissue changes, larger in size than the primary bone tumor. At the same time, the soft-tissue tumor component is homogeneous, there are no cartilaginous inclusions, foci of calcification or pathological bone formation.
If typical radiological signs of Ewing’s sarcoma are detected, the patient is sent to the oncology department, where an extended examination is carried out to assess the condition of the primary focus and detect metastases. During such an examination, computed tomography or magnetic resonance imaging of bones and soft tissues affected by the malignant process is performed. These studies allow us to accurately determine the size of the neoplasm, the degree of its spread through the bone marrow canal, the connection with the neurovascular bundle and surrounding tissues.
Computed tomography and radiography of the lungs are used to detect metastases in the lung tissue. Positron emission tomography, ultrasound and osteoscintigraphy are used to detect metastases in bones, bone marrow and internal organs. In addition, a number of studies are being carried out to accurately assess the nature of the neoplasm.
A biopsy is performed, while the material is taken from a section of bone tissue next to the bone marrow canal, or, if this is not possible, from the soft tissue component of the tumor. Since Ewing’s sarcoma is characterized by local and distant bone marrow damage, a bilateral trepanobiopsy is performed, during which bone marrow is taken from the wings of the ilium. To assess the nature of the process, an immunohistochemical study and molecular genetic studies can also be carried out (fluorescent hybridization – to confirm the diagnosis, polymerase chain reaction – to detect micrometastases).
Ewing sarcoma treatment
Since this tumor belongs to the category of highly aggressive neoplasms that metastasize early, its treatment should include an impact on the entire body, and not only on the primary focus, even in cases where metastases have not been detected. The fact is that there is a very high probability of the early appearance of micrometastases, which at the time of diagnosis cannot be detected using existing methods. Treatment of Ewing’s sarcoma is combined, includes both conservative therapy and surgical interventions and consists of the following components:
- Pre- and postoperative chemotherapy, as a rule, using several drugs (doxorubicin, vincristine, cyclophosphane, ifosfamide, etoposide and actinomycin in various combinations). After the course of treatment, the tumor’s response to therapy is evaluated. A good result is the presence of no more than 5% of living tumor cells.
- Radiation therapy using high doses. It is carried out on the primary focus, and, in the presence of metastases in the lung tissue, on the lungs.
- Surgical operation. If possible, the tumor is removed radically, together with the soft-tissue component. In this case, the removed part of the bone is replaced with an endoprosthesis. But even if, due to the location and size of the neoplasm, it is not possible to completely remove it, surgical treatment (partial resection) can improve control over the tumor and increase the chances of a successful outcome.
In the past, crippling operations – amputations and exarticulations – were usually performed with Ewing’s sarcoma. Modern techniques allow performing organ-preserving surgical interventions not only on small (fibula, radius, elbow, shoulder blade, collarbone and ribs), but also on large bones (humerus, femur and even pelvic bones). In case of metastasis to the bone marrow and bones, intensive therapy is prescribed, including total irradiation of the whole body, chemotherapy using megadoses of drugs and transplantation of peripheral stem cells or bone marrow.
Prognosis and prevention
Timely combined treatment provides 70% overall survival of patients with localized Ewing’s sarcoma. In the presence of bone and bone marrow metastases, the prognosis worsens significantly, but the combination of high-dose chemotherapy, total radiation therapy and bone marrow transplantation makes it possible to increase the survival rate of patients with metastatic disease from 10% to 30% or more.
All patients after treatment should undergo regular examination for early detection of relapses and control of side effects. It should be borne in mind that a number of side effects may occur not only during the course of treatment, but also after a long time after its completion. Such effects include male and female infertility, cardiomyopathy, impaired bone growth and an increase in the likelihood of secondary malignancies. However, many patients who have been treated for Ewing’s sarcoma can live a full life. Prevention has not been developed.
