What is Ewing’s sarcoma
Ewing’s sarcoma is a rare malignant disease that most frequently affects the bones. Less frequently, it can also occur in soft tissue (muscles and cartilage). It mainly affects children, adolescents and young adults, with a peak incidence around 15 years of age, and although rare, it is the second most frequent bone tumor in childhood and adolescence.
Males are more likely to develop the disease, at a 3:2 ratio 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.
It is a rare type of tumor: only 1% of all childhood sarcomas are Ewing’s sarcomas. In the US, about 200 people are diagnosed with the disease each year.
Types of Ewing’s sarcomas
There are three main types of Ewing’s sarcoma:
- Ewing’s sarcoma of the bone – this is the most common of the three. It occurs, as the name implies, in the bone. In order of frequency, it mostly affects the lower extremities, pelvis, chest wall, upper extremity, spine, hand and skull;
- Extra-osseous Ewing’s sarcoma – starts in soft tissue around the bones. May be difficult to differentiate from primary bone tumors; and
- Peripheral primitive neuroectodermal sarcoma (PPNET) – it is a rarer type and occurs in bone or soft tissue. In order of frequency, it mostly 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’s sarcoma
The initial symptoms of Ewing’s sarcoma are varied. Initially, a mass or swelling may be noticed at the tumor site. Another early symptom is pain at the site, which can be worse at night. The pain can be caused either by the growth of the tumor or by a fracture of the bone weakened by the disease.
Other signs and symptoms of Ewing’s sarcoma:
- Fever of unknown cause;
- Difficulty walking;
- Unexplained weight loss;
- Weakness, lack of sensation or paralysis of the arms and legs if the tumor has reached areas close to the spinal column; and
- Shortness of breath, if the tumor has spread to the lungs.
Chest wall tumors and pelvic tumors may be asymptomatic until they have grown considerably.
Ewing’s tumor diagnosis
Because many of the symptoms of Ewing’s tumor are typical of common infections, they can take time to diagnose. Often, the correct diagnosis occurs only after treatments for rheumatological and/or infectious diseases have not improved symptoms, which leads the doctor to investigate other causes.
Imaging tests are essential to identify the characteristics of the tumor and its relationship with neighboring structures. The medical team will decide which tests are needed to assess the disease, as well as its extent. Among them, the main ones are the following:
- Bone scintigraphy;
- Computed tomography;
- Magnetic resonance; and
- Positron emission tomography (PET-CT).
For a definitive diagnosis, a biopsy of the tumor is necessary.
Other tests may be needed, such as spinal taps, genetic tests, and blood tests.
Ewing’s tumor treatment
The treatment for Ewing’s tumor consists of an intensive multidrug therapy associated with local treatment – which can be a surgical resection of the tumor, with or without radiotherapy.
All 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 aiming to limit complications throughout the procedures.
Ewing tumor prevention
Ewing’s tumor cannot be prevented or avoided as it is not genetically inherited and there is no association with lifestyle or environment.