Ewing Sarcoma: What It Is, Symptoms, and Diagnosis

Ewing sarcoma is a malignant tumor that grows in bone or in the soft tissues adjacent to it. It most often occurs in adolescents and young adults.

What Ewing sarcoma is

It is a malignant tumor that forms in bones or soft tissues. It is classified within the "Ewing sarcoma family of tumors": Ewing sarcoma proper, peripheral primitive neuroectodermal tumors (PNET), and the extraosseous form outside bone. The tumor consists of small round cells and, unlike osteosarcoma, does not produce osteoid. The name comes from the American pathologist James Ewing, who described it in 1920.

Among malignant bone tumors in children, it is the second most common — 10–15%. Before the advent of systemic therapy, almost 90% of patients developed metastases.

Who gets it and what causes are known

The tumor can arise at any period of childhood and young adulthood, but usually develops during puberty, when bones grow rapidly. The peak incidence is at 10–15 years; it is rare in children under 5 years and in adults over 30. It is registered noticeably more often in White adolescents than in African and Asian countries. After 13–14 years, boys are affected about 1.5 times more often than girls.

Potential causes have not been identified. There are data on a hereditary component: cases of sarcoma developing simultaneously in siblings have been described.

Symptoms of Ewing sarcoma

There are few symptoms. The most common are pain and sometimes swelling at the tumor site. The bone weakens, so a fracture after minor trauma is possible; fever may occur.

At first the pain is mild or moderate and may ease — "pain-free intervals." It does not subside at rest, intensifies at night, and immobilization of the limb brings no relief. As the tumor grows, the pain intensifies, restricts movement in the nearest joint up to contracture, and disrupts sleep. From the first pain to diagnosis, 6–12 months often pass: the picture is blurred, and the complaints are easily explained by trauma.

Locally, there may be tenderness on palpation, redness, and swelling of the skin. Intoxication is possible: fever, weight loss and loss of appetite, weakness. With involvement of the leg, lameness appears; with involvement of the vertebrae — radiculopathy and pelvic organ dysfunction; with involvement of the chest wall — respiratory failure, hemoptysis.

How it is detected: imaging and biopsy

Examinations look for the primary tumor and its spread: radiography of the affected bone, radiography and CT of the lungs, CT or MRI of skeletal and soft tissue areas, PET, bone scintigraphy, ultrasound. CT or MRI most accurately determine the size of the tumor, its relationship to the neurovascular bundle, and spread along the medullary canal.

A biopsy is then performed: material is taken from the area of bone bordering the medullary canal or from the soft tissue component. The sample is used to assess how aggressive the process is and which treatment will be suitable. Separately, bilateral trephine biopsy of the bone marrow from the iliac wings is performed: it may be affected in isolation.

Tumor spread and metastases

The tumor grows rapidly and metastasizes early. Most often metastases are found in the lungs, then in the bones and bone marrow; rarely — in internal organs, mediastinal lymph nodes, pleura, CNS. From 14 to 50% of patients already have metastases detectable by routine methods at the time of diagnosis; many have micrometastases. Lymphatic spread is rare and always associated with a poor prognosis.

The prognosis before treatment depends on the extent of the process, the localization and size of the tumor, the level of lactate dehydrogenase (LDH), changes in the tumor genes, the child's age and sex, and also on whether he or she has previously been treated for another cancer. It makes sense to discuss survival percentages only with a doctor.

• Which examinations have already been done and which are still planned to assess the spread of the tumor.
• Whether immunohistochemical and molecular genetic testing of the sample was performed.
• Which questions to ask the doctor about the biopsy result and the further examination plan.

When to see a doctor

You should see a doctor for any of the symptoms of Ewing sarcoma: bone pain that does not go away at rest and intensifies at night, swelling, lameness, a fracture after minor trauma, unexplained fever together with weight loss. Early diagnosis increases the likelihood of a favorable outcome. Vigilance is especially needed in young people — their complaints are easily attributed to trauma.

Ewing sarcoma by itself is not a reason to call an ambulance. You should call 103 or 112 for severe difficulty breathing, hemoptysis, paralysis of the legs, or urinary incontinence.

This material is for reference: it does not replace a doctor's consultation, and decisions on examination and follow-up are made by the treating specialist together with the patient and his or her family.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer