The incidence of a secondary chondrosarcoma in Ollier disease is most commonly approximated at 25-30% with some projections even as high as 50%. Chondrosarcomas are typically developed during young adulthood and mostly form as a unifocal distribution in Ollier disease patients. The most common locations of tumors are in the pelvis and shoulder girdle. While chondrosarcoma is the most common form of a secondary malignant bone neoplasm found in cases of Ollier disease, other forms such as chordomas and osteosarcomas can occur. If left untreated, these malignant transformations may lead to fatal outcomes.