Index
They are benign tumors composed of mature hyaline cartilage. In general, they have limited growth potential and are not locally aggressive.
These tumors are called enchondromas when they occur in the medullary canal of the bone and are called periosteal or juxtacortical chondrosis when they occur on the surface of the bone.
Chondromas can also arise from the synovial tendon sheaths or in the soft tissues adjacent to the tendons in the hand and feet of adults; in such cases, they are known as synovial or soft tissue chondromas.
About 60% of enchondromas occur in the small bones of the hands and feet. The next most common sites are the long tubular bones.
Of the long bones, the femur is the most affected (17%), followed by the proximal humerus (7%). The proximal and distal metaphyses of the femur are more often involved than the diaphyses.
Enchondromas are rare in flat bones (eg, pelvis, ribs, shoulder blades, and vertebrae) and extremely rare in craniofacial bones.
Notably, they rarely affect the trunk bones, where chondrosarcomas are common. However, enchondromas are common in the axial skeleton, where chondrosarcomas are rare.
Periosteal chondromas typically appear in the long tubular bones, with 50% seen in the proximal humerus. The next most common sites are the short tubular bones of the hand.
The usual locations for chondromas of the periosteum are at the tendon attachments and are therefore metaphyseal; however, these tumors can also develop at the metaphyseal and diaphyseal sites.
Symptoms of chondromas
Econdroma
- Pain.
- Fracture.
- Tendinitis (usually in the upper arm).
- Painless swelling of a finger.
Periosteal chondromas
- Dull aching pain.
- Swelling.
- A palpable mass.
- Sometimes there are no symptoms.
Causes
The exact cause of chondromas is unknown and they account for 25% of all benign bone tumors .
Econdromas – the most common type of bone tumors found in the hand:
- Boys and girls are equally affected.
- They can occur at any age, but chondromas are usually not discovered until people are in their 30s and 40s.
Periosteal chondromas: extremely rare:
- They tend to appear earlier, which may be because they produce symptoms, leading to earlier detection.
Chondroma pathophysiology
Chondromas develop from cartilage nests on the growth plate that have become entrapped in the medullary canal of the metaphysis or at the metaphyseal-diaphyseal junction.
These hamartomatous proliferations persist as islands in bone and then develop from endochondral ossification.
They are subject to the same growth factors as normal cartilage and grow into adulthood.
Chromosomal abnormalities affecting the chromosomal region 12q13-q15 can be associated with chondroma, especially soft tissue chondroma.
In addition, some authors have reported the involvement of chromosomes 6 and 11 in a soft tissue chondroma.
Periosteal chondroma tends to develop within and below the periosteal connective tissue.
This slow-growing tumor erodes and induces sclerosis in the adjoining cortical bone, producing the characteristic “popcorn” appearance.
Synovial chondroma is the result of cartilage metaplasia of subsynovial connective tissue. Karyotypic aberration has been found to be associated with synovial chondroma (ie, trisomy 5).
Osteochondroma has also been associated with the loss of distal chromosome 8q. Multiple osteochondromatosis is associated with genetic defects in the 8q24.1 region (EXT1 gene) and in the 11p11-13 region (EXT2 gene).
epidemiology
United States and international statistics
- In the United States, benign cartilage tumors account for 27.5% of all bone tumors and 70% of all cartilage tumors.
- Enchondromas represent 12-24% of benign bone tumors and 3-10% of all bone tumors.
- Periosteal chondromas represent less than 1% of all chondromas and 0.1% of all bone tumors.
- The incidence of osteochondromas is 30% of all cartilage tumors and 2% of all bone tumors.
- International chondroma numbers do not differ significantly from U.S. numbers.
Demographic data related to age and sex
Enchondromas are distributed fairly uniformly throughout all decades of life, without preponderance of age; however, incidence peaks occur in the third and fourth decades.
Periosteal chondromas are frequently diagnosed in the second or third decades of life.
Multiple osteochondromatosis occurs slightly earlier in adolescence.
Synovial chondromas occur from the first to the seventh decade, with a peak in the fifth decade.
Sexual predilection for enchondromas is not reported: the male-female ratio is 1: 1. Similarly, there is no sexual predilection for Ollier’s disease.
Periosteal chondromas occur more commonly in male individuals than in female individuals.
Osteochondroma has a definite male preponderance, with a ratio of 1.8: 1. Synovial chondromas also show a male preponderance, with a 2: 1 ratio.
Chondromas prognosis
With proper treatment, patients with benign chondromas generally have a good prognosis, and most remain asymptomatic.
Treatment
Encondroma
Long bone enchondromas are generally asymptomatic and do not require treatment.
Curettage and histopathological evaluation are indicated if the diagnosis is uncertain, if the lesions are predominantly lytic (as seen on radiographs), if they are symptomatic and borderline in size, or if they are in any way suspicious.
For patients with pathologic fractures related to enchondromas, early surgical intervention is recommended.
Enchondromas of short tubular bones are treated with curettage and bone grafting because they tend to deform the bone contour and interfere with function.
A systematic review by Bachoura et al suggested that simple curettage of enchondromas of the hand, without increased vacuum, is safe and effective and does not increase the complication rate.
Enchondromas are rare in the axial skeleton. However, if they are found in the ribs, sternum, pelvis, or scapula, they should be treated with extensive local resection and histopathologic evaluation to rule out the possibility of chondrosarcoma , which is common at these sites.
After curettage and bone grafting, enchondromas heal well with consolidation of the graft site. If a lithic element recurs, malignancy should be ruled out.
Recurrence can affect the short tubular bones; it can be successfully treated with a second curettage procedure and histopathologic examination.
The recurrence rate is low for surgically treated hand enchondromas, and the main risk factor for recurrence is the diagnosis of multiple enchondromas; malignant transformation is rare.
Periosteal chondroma
Wide local excision is indicated for periosteal chondromas because superficial chondrosarcomas can mimic these tumors clinically and radiologically. Wide local excision is a curative procedure.
Synovial chondroma
Depending on the symptoms (especially if they are just mechanical), removal of loose bodies may be all that is required. Synovial chondroma is a local self-limited condition and can reach an inactive stage.
However, if the injury produces frequent symptoms, synovectomy may be necessary to control the disease.
Frequent recurrences with short intervening periods should raise the suspicion of synovial chondrosarcoma.
