From the Guidelines
Osteochondroma should be managed with a combination of physical examination, plain radiographs, and dedicated MRI for lesions >5-6 cm or in the pelvis/scapula, with consideration of surgical removal for symptomatic lesions or suspected malignant transformation, as the risk of chondrosarcoma is estimated to be around 0.2-5.9% 1.
Key Considerations
- The diagnosis of osteochondroma is typically confirmed through X-rays, which show the characteristic appearance of a bone growth continuous with the underlying bone's cortex and medullary cavity 1.
- Multiple hereditary exostoses (HMO) is a condition characterized by the development of multiple osteochondromas, primarily caused by pathogenic variants in the EXT1 or EXT2 genes 1.
- The risk of malignant transformation into chondrosarcoma is higher in males and individuals with an EXT1 pathogenic variant, and is estimated to occur in 0.2-5.9% of individuals with HMO 1.
Management Recommendations
- Asymptomatic osteochondromas can be managed with observation, while symptomatic lesions or those with suspected malignant transformation may require surgical removal 1.
- Physical examination and plain radiographs should be used to monitor osteochondromas, with dedicated MRI considered for lesions >5-6 cm or in the pelvis/scapula 1.
- The frequency of surveillance should be individualized based on the patient's age, symptoms, and risk factors, with consideration of whole-body MRI (WBMRI) and dedicated brain MRI for patients over 20 years or with symptoms/signs 1.
From the Research
Definition and Characteristics of Osteochondroma
- Osteochondroma is a common benign bone tumor, presenting as a single or multiple lesions, pedunculated or sessile type, mainly in 1st-2nd decades and mostly in males 2.
- It is a projection on the external surface of the bone, which can be sessile or pedunculated 3.
- Osteochondromas may be solitary (solitary osteochondroma, SO) or multiple (multiple osteochondromas MO) 4.
Clinical Manifestations and Complications
- Clinical manifestations include deformity of bone, compression of surrounding tissue and vascular or neurological compromise 4.
- Symptoms may eventuate from compression of adjacent vessels or nerves, fractures, osseous deformities, bursa formation, or malignant transformation 3.
- Pain and/or increase in size of lesions after skeletal maturation were the most common clinical signs of transformation 4.
- Malignant transformation is a rare but possible complication, more common in multiple osteochondromas (MO) than in solitary cases 3, 4, 5.
Diagnosis and Treatment
- Surgical excision is the best line of treatment for symptomatic lesions, complications, cosmetic reasons or malignant transformation 2, 3.
- Excision of the tumor with free margin is the treatment of choice, with local recurrence less than 2% if complete resection is achieved 3.
- Conservative treatment by observation and yearly radiographs is an option for asymptomatic lesions, especially in pediatric patients 6.
- Regular self-control and supplementary X-ray imaging or magnetic resonance imaging (MRI) may be needed for follow-up, especially in cases of multiple osteochondromas or lesions located in difficult-to-access anatomical regions 4.
Prognosis and Follow-up
- The risk of malignant transformation of solitary osteochondromas is generally low, but axial lesions, recurrent osteochondromas, and multiple osteochondromas seem to have an increased risk 4.
- Follow-up is necessary to monitor for potential complications or malignant transformation, with a recommended frequency of once a year after skeletal maturity for high-risk patients 4.
- Spontaneous regression of solitary osteochondromas is possible, although rare, and may occur before skeletal maturity or within 3 years of identification 6.