Musculoskeletal Teaching FileMusculoskeletal Teaching File
Osteochondroma
Also called an exostosis, these bone lesions
are benign outgrowths from long bones such as the tibia and humerus.
Rarely, they can involve the pelvis and scapula. They can be sessile
or pedunculated. They are bony outgrowths that classically grow
away from the metaphysis of the bone. They have a cartilage cap
which may calcify with age. They grow as a result of radiation
or trauma. Lesions that are large can cause pain and pressure
symptoms.
There exists a syndrome of multiple exostoses which can be
inherited. This syndrome is called diaphyseal aclasia or multiple
osteochondromas. There is a small (1%) chance of malignant degeneration
to chondrosarcoma of the cartilage cap in a solitary osteochondroma.
This percentage rises to 10% in the multiple osteochondroma syndrome.
Case prepared by Huan Nguyen, Medical Student WSU School of Medicine