osteochondroma (exostosis)

age: 10 - 30 yrs
bony outgrowth
points away from joint
site: metaphysis; long bones
- 50% at knee or shoulder
generally benign
- calcified cartilagenous cap ==> premalignant
- may --> chondrosarcoma
familial type of multiple osteochondromatoses
==> increased risk of malignancy