Unusual Presentation of Extraskeletal Mesenchymal Chondrosarcoma: A Case Report.

Mesenchymal chondrosarcomas are extremely rare and aggressive tumors that primarily affect patients between the ages of 20 and 30. These neoplasms are typically found in the lower limbs and cranial region. Their occurrence within soft tissues is exceedingly rare, and the initial presentation often includes immediate metastatic dissemination. Given the extraordinarily low prevalence of extraskeletal mesenchymal chondrosarcoma, treatment approaches remain non-standardized. Surgical resection combined with neoadjuvant chemotherapy or radiotherapy is the most commonly favored strategy by medical teams. In this case report, we present the case of a 72-year-old patient with no specific medical history, who presented with a non-metastatic extraskeletal mesenchymal chondrosarcoma located in the popliteal fossa. The therapeutic intervention encompassed surgical resection followed by adjuvant radiotherapy. After 18 months of follow-up period, there was no evidence of local recurrence or distant metastases. The disparity between the patient's clinical characteristics and the existing medical literature may provide new insights into understanding this neoplastic entity.