Imaging Findings of Retroperitoneal Primary Extraskeletal Mesenchymal Chondrosarcoma: A Case Report

Imaging knowledge regarding retroperitoneal primary extraskeletal mesenchymal chondrosarcoma (ESMC) is limited. We report a new case of ESMC originated from the retroperitoneum. The tumor was indicated a well-defined mass with marker calcification, the parenchyma showed gradual enhancement pattern on the biphasic enhanced computed tomography and wash-in-wash-out enhancement pattern on the contrast-enhanced magnetic resonance imaging and hyperintensity on diffusion-weighted imaging which implying the dense cellularity of tumor cells. Sonography indicated an increased echogenicity nodular area in the mass. These imaging features further enriched the imaging knowledge of this rare tumor and presented valuable imaging characteristics to diagnose retroperitoneal primary ESMC.