[Extraskeletal mesenchymal chondrosarcoma: a case report and review of the literature].

We report a new case of mesenchymal chondrosarcoma in a 25-Year-old woman who presented a tumefaction of the anteromedial aspect of the mid left leg which had developed over two Years. Computed tomography of the lower left limb demonstrated the presence of a soft tIssue tumor limited to the gastrocnemus medial. The 7.5 x 5 cm tumor was centered on a zone of calcification. Histological examination confirmed the diagnosis of malignant mesenchymatous proliferation with two components: a well differentiated cartilaginous component and a totally undifferentiated component. Surgical resection was performed but tumor recurrence was observed in the popliteal fossa as well as a pulmonary metastasis with a unique parenchymal nodule. Amputation of the left lower limb and metastasectomy were performed. At last follow-up, the patient presented permeation nodules on the scalp.