OBJECTIVETo explore the clinicopathologic features of Ollier's disease, its chondrosarcomatous transformation and related differential diagnoses.

METHODSA total of 19 cases of Ollier's disease and 8 control cases of pure multiple enchondroma were investigated by imaging studies including X-ray, CT or MRI, and hematoxylin and eosin stain.

RESULTSAmong 19 cases of Ollier's disease, 12 were men and 7 were women with a mean age of 20 years (range, 5-66 years). Ollier's disease involving short tubular bones of extremity were lytic defects with bony expansion, thinning or disappearance of the overlying cortex surrounded by periosteal fibrous tissues. When occurring in the long bones, the disease showed radiolucent columns of dysplastic cartilage that extended from the metaphysis to diaphyseal and created bowing deformation and limb asymmetry. Microscopically, the cartilage present in the small bones of the hands and feet tended to be more hypercellular with more abundant enlarged or binucleated nuclei. The lesion in long bones appeared multicentric, surrounding with a thin rim of bone and calcification. Six cases of Ollier's disease had developed secondary low-grade chondrosarcoma.

CONCLUSIONSLow-grade chondrosarcomatous transformation can occur in dysplastic cartilage of Ollier's disease. The diagnosis of such sarcomatous transformation should be determined by invasion, but not atypicality of the cartilagenous cells. There are certain differences between the secondary chondrosarcoma of Ollier's disease and conventional chondrosarcoma on clinical, radiographical and pathological grounds.