Osteochondroma (synonyms: ecchondroma; exostosis; cartilaginous exostosis; solitary osteochondroma; solitary exostosis; hereditary multiple exostoses; multiple osteocartilaginous exostoses; ICD-10 D16.9: Benign neoplasm of bone and articular cartilage, unspecified) is a benign (benign) bony tumor with a cartilage cap that arises spontaneously from excessive growth of bone and cartilage. It sits on top of the bone and displaces the surrounding soft tissue. The shape of the osteochondroma resembles a fungus.
In most cases, an osteochondroma is localized near the joint. In children, it grows from the not yet ossified epiphyseal joint (growth plate).
The osteochondroma belongs to the primary tumors. Typical for primary tumors is their respective course and that they can be assigned to a certain age range (see “Frequency peak”) as well as a characteristic localization (see under “Symptoms – complaints”). They occur more frequently at the sites of most intensive longitudinal growth (metaepiphyseal/articular region). This explains why bone tumors occur more frequently during puberty. They grow infiltratively (invading/displacing), crossing anatomical boundary layers. Secondary bone tumors also grow infiltratively, but usually do not cross boundaries.Osteochondroma stops growing after body growth is complete and ossifies completely. As long as the tumor has not ossified, it is referred to as an ecchondroma.
An osteochondroma can occur solitary (single) (SO; solitary cartilaginous exostosis), but also multiple (MO; osteochondromatosis/multiple osteocartilaginous exostoses; ICD-10 D48.0: neoplasm of uncertain or unknown behavior on bone and articular cartilage). The latter describes a hereditary systemic disease with a higher risk of degeneration. Defects in the length and shape of growing bones may occur as part of the disease.The following information refers to solitary osteochondroma (SO).
Sex ratio: boys/men to girls/women is 1.8: 1.
Peak incidence: osteochondroma occurs predominantly between the ages of 10 and 35.
Osteochondroma is the most common benign bone tumor. It accounts for approximately 50% of benign bone tumors and 12% of all bone tumors.
The course and prognosis depend on the location and extent of the bone tumor. In general, benign (benign) tumors can initially be waited for and observed (“watch and wait” strategy). Osteochondroma rarely causes symptoms and is usually discovered by chance. Symptoms only appear when the tumor increases in size and presses on or displaces other structures such as nerves, blood vessels or muscles or impairs joint mobility. Then the osteochondroma is usually resected (surgically removed). Because osteochondroma is a benign tumor, it does not form metastases (daughter tumors). The prognosis is very good. It is estimated that an osteochondroma recurs in 2% of cases.
An osteochondroma can degenerate, that is, become malignant (malignant). However, this is very rare in a solitary osteochondroma (< 1% and after the 18th LJ, usually after the 40th LJ). The risk of degeneration in osteochondromatosis is 2-5%. Risk factors for degeneration are:
- Localization close to the trunk or osteochondroma located at the trunk.
- Thickness of the cartilage cap > 20 mm
- Growth of the osteochondroma in adulthood.
- Recurrent osteochondroma (recurrence of osteochondroma).
- Multiple osteochondromas (osteochondromatosis)
