Mesenchymal chondrosarcoma is a rare chondroid tumor that was first reported in 1959 by Lichtenstein et. al. Twenty-seven cases with mesenchymal chondrosarcoma of bone and twenty-one cases with that of soft part have only been reported in Japan. We have treated both cases.
The first case, that was a mesenchymal chondrosarcoma of the sacrum, was treated with wide resection. Irradiation was performed as an adjuvant therapy after the surgery. However, the patient died of local recurrence, pulmonary and liver metastasis five years and eight months after the surgery.
The second case, that was a mesenchymal chondrosarcoma of the paravertebral muscle, was treated with the excision of the tumor and the hemilaminectomy of the second and third vertebrae. Local recurrence and distant metastasis were not observed ten months after the surgery.