Question: How Can We Tell The Difference Between Enchondroma And Low-grade Chondrosarcoma?

What is low-grade chondrosarcoma?

Type of tumour: malignant, slow-growing cartilage tumour.

Location: Long bones, flat bones (pelvis) and ribs.

Symptoms: Deep continuous dull pain.

Risk factors: Increased age, and there is a 40% risk of patients with Ollier and Mafucci syndrome developing chondrosarcoma, which depends on age. Patients with endochondroma in the long bones and the pelvis (axial) have an increased risk of developing chondrosarcoma. Thus, regular screening is needed to detect malignant transformation.

What is an enchondroma?

• Type of tumour: Benign cartilage tumour
• Location: Mostly found in the long bones (proximal humerus, distal femur, or proximal tibia metaphyses),
• Age of onset: 10 to 40 years.
• Symptoms: Patients have no symptoms and are diagnosed via X-rays in the small bones of the hands and feet.
• Size of tumour: Enchondromas are typically smaller than 5 cm, and 80% of enchondromas in the long bones are smaller than 2 cm.
• Risk factors:
• The risk is small if it affects a small area, but if it is caused by rare genetic conditions, the risk increases, causing malignant multiple enchondromas.
• Examples of genetic conditions are Ollier’s disease and Mafucci syndrome.

What is the difference between Ollier’s disease and Maffucci syndrome?

The extent to which it is distributed in the body.

Ollier’s disease, otherwise known as dyschondroplasia, has unequal distribution of benign cartilaginous tumours in the body. It is caused by malformed ossification of cartilages. The tumours lead to stunted growth and deformation.

Maffucci syndrome causes enchondroma and soft tissue vascular growths called hemangioma. This causes a greater risk and is linked to the size and number of lesions, especially in the pelvis and long bones.

Classification of endochondroma and low-grade chondrosarcoma

Endochondroma and low-grade chondrosarcoma are classified as part of atypical cartilaginous tumours (ACT) in the APPENDICULAR skeleton, particularly long bones, by the World Health Organisation in 2013 and 2020.

They are intermediate chondroid tumours because of their rarity of metastasis but are locally aggressive and have a better clinical outcome than the same tumour in the axial skeleton (<2%).

Since the World Health Organisation (2020), the same lesions of Endochondroma and low-grade chondrosarcoma are also classified as grade 1 chondrosarcoma in the AXIAL skeleton (scapula, pelvis, ribs, spine, sternum (breastbone) and skull) because they have a poorer outcome.

If there are multiple lesions or in the pelvis, it can cause chondrosarcoma in solitary osteochondroma and enchondroma.

Table 1 Classification of malignant primary bone tumours (WHO, 2020)

Diagnosis of enchondroma and chondrosarcoma

Both enchondroma and low-grade chondrosarcoma vary in the outcomes of diagnosis and treatment.

The tests that can be done are in the form of X-ray, Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and the study of tissues (histology). A sample of this is extracted via biopsy of the concerned area to be visualised under the microscope by a histopathologist.

The role of CT in the diagnosis of enchondroma and ACT

It is not a routine imaging test for enchondroma and ACT.

However, if the MRI/X-ray does not help with the diagnosis, it is used to detect the following:

• Subtle matrix mineralization.
• To measure the amount of bone destruction in axial lesions, e.g., skull or pelvis, and the extent of the tumour if it has reached the joint.
• It can help detect whether there is expansion and cortical destruction.
• It helps to detect other pathological fractures.

Features to distinguish enchondroma and chondrosarcoma

Supporting Images And Resources

Treatment differences between enchondroma and chondrosarcoma

Enchondromas are benign and do not require follow-up.

High-grade chondrosarcomas are treated with wide resection, since they are insensitive to chemotherapy and radiation.

Over time, treatment of ACT has shifted towards the conservative side, i.e. watchful waiting or “wait and scan” by MRI instead of curettage.

Recommended source

https://radiologyassistant.nl/musculoskeletal/bone-tumors/chondrotumors-1

References

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Updated July 2026 Next Review July 2028