INTRODUCTION

Chondrosarcomas are a heterogeneous group of malignant bone tumors that share in common the production of chondroid (cartilaginous) matrix [1]. Chondrosarcomas are the third most common primary malignancy of bone after myeloma and osteosarcoma [2]. They account for 20 to 27 percent of primary malignant osseous neoplasms [3].

Clinical behavior is variable. Ninety percent are conventional chondrosarcomas, 90 percent of which are low- to intermediate-grade tumors [4]. These tumors are slow growing with a low metastatic potential. They are considered relatively refractory to chemotherapy and radiation therapy.

In contrast, high-grade chondrosarcomas, which include 5 to 10 percent of conventional chondrosarcomas as well as some rare variants, have a high metastatic potential and a poor prognosis following resection alone [4]. Some of the rare subtypes are more responsive to chemotherapy and radiation.

This topic review will provide an overview of the classification, clinical characteristics, and therapeutic options for chondrosarcoma. The rare chondrosarcomas involving the head and neck and skull base, as well as diagnosis and biopsy techniques for bone sarcomas in general, are discussed elsewhere. (See "Chordoma and chondrosarcoma of the skull base" and "Head and neck sarcomas" and "Bone tumors: Diagnosis and biopsy techniques".)

HISTOLOGIC GRADING AND PROGNOSIS

Histologic grade is one of the most important indicators of clinical behavior and prognosis [5-8]. Chondrosarcomas are graded on a scale from 1 to 3, based upon nuclear size, staining pattern (hyperchromasia), mitotic activity, and degree of cellularity (picture 1) [3,9].