 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.A related and even rarer disorder named Maffucci syndrome is a very similar condition that is characterized by the presence of multiple enchondromas with hemangiomas and occasionally lymphangiomas usually near the hands and feet but not limited to the skull, ribs, and spinal bones.