Radiological and multidisciplinary management of extraskeletal myxoid chondrosarcoma: A case report

Extraskeletal myxoid chondrosarcoma (EMC), a very rare subtype of soft tissue sarcoma (STS), distinguished by its histopathological profile, has unique clinical prognosis of potential for late local recurrences and distant metastases due to its molecular alterations. The infrequent occurrence of EMC, coupled with its radiological characteristics that often overlap with those of other myxoid-rich neoplasms, may impose considerable diagnostic difficulties for clinicians. A 43-year-old male who presented with a progressively enlarging mass in the distal right thigh and knee region since six-month prior. Initial imaging studies, including computed tomography (CT) and non-contrast magnetic resonance imaging (MRI), suggested a diagnosis of liposarcoma. However, further evaluation including a comprehensive contrast-enhanced MRI revealed a large multilobulated, well-defined soft tissue mass at the distal anteromedial femur. The lesion demonstrated isointense to hypointense signal on T1-weighted sequence and hyperintensity on T2-weighted/STIR sequences reflecting myxoid matrix, and prominent peripheral and septal enhancement post-gadolinium administration. The mass also exhibited local bone erosion and infiltration into surrounding musculature and the knee joint. A core needle biopsy followed by immunohistochemical profiling was consistent with a diagnosis of EMC. Following multidisciplinary consultation, the patient underwent successful limb salvage surgery, involving wide excision of the tumor and reconstruction using prosthesis. This case underscores the critical role of advanced imaging techniques in characterizing soft tissue masses and suggesting EMC in the differential diagnosis prior to histopathological confirmation. Moreover, multidisciplinary approach for the effective management of this rare sarcoma, including complex surgical reconstruction to preserve limb function is essential.