What is Ewing sarcoma
Ewing sarcoma is a rare malignant disease representing 1% of all childhood sarcomas. In the US, about 200 people are diagnosed with the disease each year.
It can originate mainly in bones (82% of cases) or less commonly in soft tissues (muscles adjacent to bones) (18% of cases). It affects children, teenagers, and young adults, peaking in incidence around 15 years of age, and although rare, it is the second most common bone tumor in childhood and adolescence.
Males are more likely to develop the disease, in a ratio of 3:2 compared to females.
The cause of Ewing’s tumor is unknown, and there are no risk factors associated with its development. There is no evidence that it is a hereditary disease.
Subtypes of Ewing Sarcoma
There are three main types of Ewing sarcoma:
- Ewing Sarcoma of Bone – This is the most common of the three. It occurs, as the name suggests, in the bone. In order of frequency, it affects the pelvis, chest wall, femur, tibia and fibula, humerus, ulna, spine, hand, and skull;
- Extraosseous Ewing Sarcoma – It starts in soft tissues around the bones. It can be difficult to differentiate from primary bone tumors; and
- Peripheral Primitive Neuroectodermal Tumor (pPNET) – This is rarer and occurs in bone or soft tissues. In order of frequency, it affects the trunk, extremities, head and neck, and retroperitoneum. When it starts in the chest wall, it is called an Askin tumor.
Symptoms and Signs of Ewing Sarcoma
The initial symptoms of Ewing sarcoma can vary. Initially, a mass or swelling at the tumor site may be noticed. Another early symptom is pain at the site, which may be worse at night. The pain can be caused by both the tumor growth and a fracture of the bone weakened by the disease.
Other signs and symptoms of Ewing sarcoma:
- Fever of unknown origin;
- Fatigue;
- Difficulty walking;
- Unexplained weight loss;
- Weakness, numbness, or paralysis of the arms and legs if the tumor has affected areas near the spinal cord; and
- Shortness of breath if the tumor has spread to the lungs.
Tumors of the chest wall and pelvic tumors can be asymptomatic until they have grown considerably.
Diagnosis of Ewing’s tumor
As many of the symptoms of Ewing’s tumor are typical of common infections, they may take time to be diagnosed. Often, the correct diagnosis occurs only after treatments for rheumatic or infectious diseases that have not improved, leading the doctor to investigate other causes for the complaint.
Imaging tests are essential to identify the characteristics of the tumor and its relationship with neighboring structures. The medical team will decide which ones are necessary for the evaluation of the disease, as well as its extent. Among them, the main ones are:
- X-ray;
- Bone scintigraphy;
- Computed tomography;
- Magnetic resonance imaging; and
- Positron emission tomography (PET-CT).
For a definitive diagnosis, a biopsy of the tumor is necessary.
Other tests may be required, such as bone marrow biopsy, genetic tests, and blood tests.
Treatment for Ewing’s sarcoma
Treatment for Ewing’s sarcoma consists of intensive chemotherapy along with local treatment, which can be surgical resection of the tumor, with or without radiation therapy.
The entire treatment should be guided by the patient’s chance of cure, by preserving the function of the parts of the body affected by the tumor (as much as possible), and by taking care to limit complications throughout the procedures.
Prevention of Ewing’s sarcoma
Ewing’s sarcoma cannot be prevented or avoided, as it is not genetically inherited and there is no association with lifestyle or environment.
