Extra-osseous Ewing’s Sarcoma Metastatic

Extra-osseous Ewing’s sarcoma metastatic is a rare and aggressive form of cancer that originates in soft tissues rather than bones and has spread to other parts of the body. This condition shows aggressive clinical behavior with high rates of distant spread, requiring a comprehensive treatment approach combining multiple therapies.

Table of contents

• What is Extra-osseous Ewing’s Sarcoma?
• Where Does It Develop?
• Who Gets This Disease?
• Symptoms and Warning Signs
• How Doctors Diagnose the Condition
• Treatment Approaches
• Understanding Outcomes

What is Extra-osseous Ewing’s Sarcoma?

Extraosseous Ewing sarcoma (EES) is a rare tumor that originates from soft tissues rather than bones^[1]. It belongs to the Ewing sarcoma family of tumors, which includes several related conditions that share similar characteristics under the microscope and genetic features^[2].

These tumors affect the body’s soft tissues, which connect, support, and surround other body parts and organs. Soft tissues include muscles, tendons, and ligaments^[3]. When Ewing sarcoma begins in tissue other than bone, it is called extraosseous Ewing sarcoma^[4].

The disease is poorly differentiated and highly malignant, meaning the tumor cells do not look or function like normal cells and grow very aggressively^[1]. It shows aggressive clinical behavior with high rates of local recurrence and distant metastasis, which means the cancer can come back in the same area or spread to other parts of the body^[1].

Where Does It Develop?

Commonly affected sites for extraosseous Ewing sarcoma include the paravertebral spaces (areas next to the spine), lower extremities (legs), head and neck, and pelvis^[1]. Other rare locations include the retroperitoneum (the space behind the abdominal organs), omentum (a fold of tissue in the abdomen), orbit (eye socket), skin, and chest wall^[1].

Extraskeletal tumors are more likely to arise from axial locations (areas along the central axis of the body) and less likely to arise from the pelvis compared to bone-based Ewing sarcoma^[1]. A secondary involvement of bones is rare, even when the disease has spread^[1].

Who Gets This Disease?

Patients with extraosseous Ewing sarcoma tend to be older on average and are less likely to be male or White compared to patients with skeletal tumors^[1]. While typical Ewing sarcoma of the bone most commonly affects people between ages 10 and 20, extraosseous forms can occur at different ages^[2].

Symptoms and Warning Signs

The clinical picture of extraosseous Ewing sarcoma depends mainly on the primary site of the tumor^[1]. Symptoms may include pain, swelling, or a noticeable lump at the site of the tumor^[2].

When the cancer has spread (metastatic disease), additional symptoms may appear, such as fatigue and unexpected weight loss^[3]. The tumor may be present for many months before it becomes large enough to cause noticeable symptoms^[2].

How Doctors Diagnose the Condition

The available diagnostic tools include several types of imaging and laboratory tests. Ultrasonographic evaluation uses sound waves to create pictures of the inside of the body^[1]. Computed tomography (CT) and magnetic resonance imaging (MRI) provide detailed images of soft tissues and help doctors see the extent of the tumor^[1].

A definitive diagnosis requires histopathologic and immunohistochemical tissue examination, which means taking a sample of the tumor and examining it under a microscope using special staining techniques^[1]. Several genetic biomarkers have been established to help identify this type of cancer, although their use needs to be further tested by larger studies^[1].

Treatment Approaches

Patient characteristics and outcomes appear to be different in extraosseous Ewing sarcoma compared to patients with skeletal Ewing sarcoma, which has implications for patient care and prognosis^[1]. However, multimodality therapeutic strategies (using multiple types of treatment together) are recommended for all types of the Ewing tumor family^[1].

Treatment for Localized Disease

For localized disease (cancer that has not spread), the recommended treatment remains surgery to remove the tumor^[1]. However, chemotherapy (drugs that kill cancer cells) can be added to achieve improved survival^[1].

Neoadjuvant regimens (chemotherapy given before surgery) show more promising results than adjuvant regimens (chemotherapy given after surgery)^[1]. Radiotherapy (treatment using high-energy rays) is an option to obtain local control of the tumor, although its complications have reduced its use^[1].

Treatment for Metastatic Disease

In metastatic or recurrent disease (when cancer has spread or come back), systematic chemotherapy improves survival^[1]. A case report described successful treatment of metastatic extraosseous Ewing sarcoma with pazopanib, a targeted drug, in a patient who had received multiple previous treatments. The response lasted for more than 26 months, suggesting this drug may be a therapeutic option^[10].

Understanding Outcomes

About 25% of patients with Ewing sarcoma present with upfront clinical metastatic disease, while 80-90% have subclinical microscopic widespread disease at baseline^[16]. The outcome of patients with upfront metastasis is difficult, with long-term cure in 20-30% of patients despite aggressive chemotherapy and local therapy^[16].

Meticulous selection of patients with metastatic disease may help in treating good-risk patients with aggressive systemic and local therapy while helping to spare serious toxicity to patients with widespread poor-risk metastatic disease^[16].