Extraskeletal myxoid chondrosarcoma with massive pulmonary metastases

Area of Science:

• Oncology
• Rare Cancers
• Mesenchymal Neoplasms

Background:

• Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignancy characterized by NR4A3 gene rearrangements.
• Typically affects adults around age 50, arising in deep tissues of extremities and limb girdles.
• EMC exhibits indolent growth but a high propensity for local recurrence and metastasis.

Observation:

• A 41-year-old woman presented with a large left thigh mass (EMC).
• Recurrence occurred in the pelvis and lungs despite initial wide local resection.
• The patient achieved prolonged disease control with pazopanib (a tyrosine kinase inhibitor) and radiation therapy after failing other treatments.

Findings:

• Pazopanib demonstrated efficacy in managing advanced extraskeletal myxoid chondrosarcoma.
• Disease progression was noted after pazopanib dose reduction and discontinuation.
• Tumor growth acceleration after TKI withdrawal is a potential concern in EMC.

Implications:

• While surgery and radiation remain primary treatments for EMC, TKIs represent a viable systemic option for selected patients.
• Further research into TKIs and immunotherapies is crucial for improving EMC care.
• Basket trials targeting unique genomic features like NR4A3 rearrangements in EMC are essential for discovering novel treatments.