Diagnosis and Management of Enchondromas

Initial Imaging Assessment

Conventional radiographs in two planes should be the first investigation, followed by MRI of the entire compartment with adjacent joints for local staging, and contrast-enhanced MRI can reveal high-grade areas that may guide biopsy, as recommended by the American Academy of Orthopaedic Surgeons 1, 2
MRI is essential for local staging and can help identify high-grade areas that may require biopsy, with a strength of evidence supported by multiple studies 1, 2

Biopsy is recommended for enchondromas > 5-6 cm, especially in high-risk locations like the humerus, due to the increased risk of malignant transformation, as supported by the American Academy of Orthopaedic Surgeons and other societies 1, 2

Biopsy should be performed at a bone sarcoma reference center by the surgeon who will carry out any potential definitive tumor resection, using core-needle biopsy under imaging control, with a moderate strength of evidence 1, 2

If confirmed benign enchondroma, management options include surveillance with physical examination and imaging, with regular follow-up recommended by general guidelines 1, 2
If low-grade chondrosarcoma, grade I chondrosarcomas in long bones can be managed by curettage with adjuvant treatment, while higher-grade chondrosarcomas require wide surgical excision, with a high strength of evidence supporting these recommendations 1, 2
Treatment options include curettage, microfracture, mosaicplasty, wide surgical excision, radiation therapy, and chemotherapy, as stated by the National Comprehensive Cancer Network 3 and the American Academy of Orthopaedic Surgeons 4, 5

Histological grading of cartilaginous tumors can be challenging with significant inter-observer variability, even among experts, highlighting the need for careful evaluation and consideration of multiple opinions 1, 2
Pain at the site of a cartilaginous lesion may indicate malignant transformation and should prompt immediate evaluation, with a moderate strength of evidence supporting this recommendation 1
The following classification systems are used to grade chondroid lesions:

Enchondromas are primarily caused by somatic mutations in IDH1 or IDH2 genes, which occur in approximately 80% of cases and lead to abnormal cartilage growth within the medullary cavity of bones 6
Somatic mutations in IDH1 and IDH2 genes are associated with enchondromas, causing somatic mosaicism rather than constitutional alterations, and germline mutations in PTHR1 are less commonly associated with enchondromas 6
Enchondromas can involve the axial skeleton (pelvis and ribs) and typically occur in the metaphyseal region of long bones 6, 2
Multiple enchondromas (enchondromatosis) can occur, including Ollier Disease and Maffucci Syndrome, with a higher risk of malignant transformation 6
Up to 30% risk of malignant transformation in Ollier Disease and Maffucci Syndrome, with a higher risk in specific locations: femur, tibia, humerus, pelvis, and scapula, and transformation typically occurs at median age of 30-52 years 6

Physical examination every 6-12 months and plain radiographs of known lesions every 2-3 years are recommended for patients with enchondromas, especially multiple ones, according to the American Academy of Orthopaedic Surgeons 6
Dedicated MRI for lesions >5-6 cm or in high-risk locations (pelvis/scapula) should be considered, and whole-body MRI at diagnosis and periodically after age 20 for patients with enchondromatosis is recommended 6
Surveillance recommendations include physical examination, imaging of the lesion, and chest radiograph every 6-12 months for 2 years, then yearly as appropriate, for low-grade lesions, according to the National Comprehensive Cancer Network 3
Prognostic factors include metastatic disease at presentation, histological grade, axial primary site, and size of the lesion, according to the American Academy of Orthopaedic Surgeons 4