Chondroblastic Osteosarcoma

Chondroblastic osteosarcoma is defined as a high-grade bone tumor with a substantial volume (up to 90%) of tissue with a chondrosarcomatous phenotype next to osteoid-forming areas. It is a rare tumor with a reported overall prevalence between 5% to 25% of all osteosarcomas and with a similar age distribution to osteosarcomas. The familiar periosteal osteosarcoma is a moderately differentiated chondroblastic osteosarcoma.

The problem with chondroblastic osteosarcoma is sampling error during biopsy due to the high chondrosarcomatous component, which may lead to misdiagnosis and mistreatment.

Therefore, chondroblastic osteosarcoma has to be considered when the diagnosis of chondrosarcoma is entertained in a relatively young patient without a previous history of benign cartilaginous tumor such as an enchondroma.

References

Geirnaerdt MJ, Bloem JL, van der Woude HJ, Taminiau AH, Nooy MA, Hogendoorn PC. Chondroblastic osteosarcoma: characterisation by gadolinium-enhanced MR imaging correlated with histopathology. Skeletal Radiol. 1998 Mar;27(3):145-53.