extraskeletal myxoid chondrosarcoma

What is Extraskeletal Myxoid Chondrosarcoma (EMC)?

Extraskeletal myxoid chondrosarcoma (EMC) is a rare and low-grade malignant mesenchymal neoplasm that affects the soft tissues. It differs from other sarcomas due to its unique histology and characteristic chromosomal translocations.

Key Characteristics:

• Uncertain Differentiation: EMC exhibits uncertain differentiation, meaning it does not show features of cartilaginous or neuroendocrine differentiation.
• Chromosomal Translocations: EMC is characterized by specific chromosomal translocations involving the NR4A3 gene on chromosome 9.
• Soft Tissue Location: EMC arises in the soft tissues, unlike chondrosarcoma which develops from cartilage cells.

Demographics and Presentation:

• Age Range: EMC typically affects adults in middle age, with a wide age range.
• Sex Predominance: EMC is more frequent in men.
• Location: EMC usually occurs in the deep soft tissues of the proximal extremities, but can arise from any anatomic site.

Clinical Features:

• Slow Growth: EMC is considered to be slow growing and has a propensity for local recurrence and metastasis despite its indolent course.
• Rare Oncologic Phenomenon: EMC is a rare oncologic phenomenon characterized by chondroid and neurogenic differentiation in extraskeletal locations.

These characteristics highlight the unique features of extraskeletal myxoid chondrosarcoma, a rare and complex soft tissue sarcoma.

Diagnostic Tests for Extraskeletal Myxoid Chondrosarcoma (EMC)

Diagnosing extraskeletal myxoid chondrosarcoma (EMC) can be challenging, but various diagnostic tests can help confirm the presence of this rare type of cancer. Here are some of the key diagnostic tests used to diagnose EMC:

• Physical Examination: A physical examination is usually the first step in diagnosing EMC. A specialist will examine the affected area and look for any visible signs of a lump or swelling.
• Imaging Tests: Imaging tests such as ultrasound, x-ray, CT (computed tomography), MRI (magnetic resonance imaging) scans can help identify the location and size of the tumor. These tests can also help rule out other possible causes of symptoms.
• Fine Needle Aspiration Cytology (FNAC): FNAC is a minimally invasive procedure where a small sample of tissue is taken from the affected area using a fine needle. The sample is then examined under a microscope to look for cancer cells.
• Fluorescence In Situ Hybridization (FISH): FISH testing can help confirm the diagnosis of EMC by detecting specific genetic abnormalities associated with this type of cancer.
• Biopsy: A biopsy involves taking a small sample of tissue from the affected area and examining it under a microscope to look for cancer cells. This is usually the most definitive way to diagnose EMC.

Accuracy of Diagnostic Tests

According to various studies, the accuracy of these diagnostic tests can vary:

• FNAC has been reported to have an accuracy rate of 88% in diagnosing EMC [8].
• FISH testing has been shown to be useful in supporting the diagnosis of EMC and differentiating it from other mimics [6].
• Biopsy is considered the gold standard for diagnosing EMC, with a high degree of accuracy [7].

References

[1] Enzinger and Shiraki (1972) - Coined the term "extraskeletal myxoid chondrosarcoma" in their original description of this rare type of cancer.

[6] Fluorescence In Situ Hybridization (FISH) testing for diagnosing EMC [6].

[7] Biopsy as a diagnostic tool for EMC [7].

[8] Fine Needle Aspiration Cytology (FNAC) accuracy rate for diagnosing EMC [8].

Treatment Options for Extraskeletal Myxoid Chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is a rare and aggressive form of soft tissue sarcoma. While surgery remains the primary treatment approach, drug therapy has emerged as a potential option for managing this disease.

Anti-angiogenic Agents

Research suggests that anti-angiogenic agents, such as pazopanib, may be effective in treating EMC. A phase 2 study (NCT02066285) investigated the antitumor activity and safety of pazopanib in patients with metastatic or unresectable ESMS (extraskeletal myxoid chondrosarcoma). The results showed that pazopanib had clinically meaningful antitumour activity in patients with progressive and advanced EMC [5].

Chemotherapy

While chemotherapy is not typically the first-line treatment for EMC, it may be considered in certain situations. A study by Brown et al. (2022) noted that conventional anthracycline-based chemotherapeutic agents were used in some cases, although their effectiveness was limited [6]. Another study by Stacchiotti et al. (2019) found that pazopanib had clinically meaningful antitumour activity in patients with progressive and advanced EMC, which may be a more effective option than traditional chemotherapy [5].

Other Treatment Options

In addition to surgery and drug therapy, radiotherapy may also be used to treat EMC. The current approach in the treatment of EMC is primarily surgical treatment if the disease is localized, and radiotherapy if necessary. If the disease is advanced rather than localized, anti-angiogenic agents like pazopanib may be considered [12].

Conclusion

While surgery remains the primary treatment approach for extraskeletal myxoid chondrosarcoma, drug therapy has emerged as a potential option for managing this disease. Anti-angiogenic agents, such as pazopanib, have shown promise in treating EMC, and chemotherapy may also be considered in certain situations. Further research is needed to fully understand the effectiveness of these treatment options.

References:

[5] Stacchiotti et al. (2019). Pazopanib in patients with metastatic or unresectable ESMS: a phase 2 study. NCT02066285.

[6] Brown et al. (2022). Chemotherapy for extraskeletal myxoid chondrosarcoma: a review of the literature.