Secondary chondrosarcoma in osteochondromas. Medullary extension in 15 of 45 cases.

We reviewed 45 secondary chondrosarcomas: 16 arising in solitary osteochondromas and 29 in 27 patients with multiple osteochondromas. Less than radical or wide primary surgery resulted in local recurrence in 8 of 14 lesions: 2 of 2 intralesional excisions, 5 of 11 marginal excisions, and in one case with radiotherapy alone. No local recurrence was found after a primary wide surgical procedure in 30 lesions and a radical procedure in 1 lesion after a mean of 8 (0.2-22) years' follow-up. 5 patients had died: 3 of pulmonary metastases (2 stage IB, 1 stage IIB), and 2 of local tumor invasion, both in the spine. Medullary invasion occurred in 15 of 45 lesions, this was often than reported in secondary chondrosarcoma. Medullary invasion was not always detected preoperatively, even when MR or CT examinations had been performed. Therefore, we recommend that a secondary chondrosarcoma should be removed with a wide surgical resection, including a part of the underlying bone, to keep the local recurrence risk low. There were no clinical or prognostic differences between tumors that had arisen from solitary or from multiple osteochondromas.