Pathogenesis (disease development)
Osteochondroma is a benign (benign) bone growth. It develops spontaneously during body growth due to excessive growth of bone and cartilage. In this process, parts of the growing cartilage extend from the metaphyseal epiphyseal joint (growth zone) into the soft tissues. This so-called exostosis (bony outgrowth developing from the bone surface) initially grows laterally, but can be deflected by pressure from the surrounding soft tissue mantle. In about 90% of cases, the exostosis grows in a style (pedicular), sometimes broad-based (sessile), and is covered by a thin layer of cartilage. In its shape it resembles a fungus. Characteristic is a spongy (sponge-like) connection of tumor and bone.
Osteochondroma stops growing after completion of body growth and ossifies completely. As long as the tumor has not ossified, it is called an ecchondroma.
Etiology (Causes)
The exact causes of osteochondroma are still unclear. The multiple occurrence of osteochondromas, osteochondromatosis (multiple osteocartilaginous exostoses), is hereditary.
Biographic causes
- Genetic burden
- Osteochondromatosis is inherited in an autosomal dominant manner.
- Known chromosomal defects: on chromosome 8q24 [EXT1] and 11p11-13 [EXT2].
- Osteochondromatosis is inherited in an autosomal dominant manner.
