Enchondroma is a benign cartilage forming tumor. Commonly occurs in childhood, but not recognized until 20- 30 years of life due to asymptomatic nature. They are located in shaft or diaphysis of short bones of hand, feet and long bones of limbs. Men and women are equally affected.
What is cause of enchondroma?
Etiology of enchondroma is unknown. Familial pattern with multiple family members are affected rarely. Multiple enchondromas are associated with syndromes such as Ollier’s Disease (Non Hereditary), Mafucci’s Syndrome (Hemangioma of soft tissues). Multiple enchondromatosis may result in deformity of the involved bone. Both solitary and multiple enchondromas (higher) are at a risk of transformation into Chondrosarcoma (The true incidence is not known since most of enchondromas are asymptomatic and are not detected).
How is enchondroma identified?
Most individuals have no symptoms. They are discovered incidentally when undergoing radiograph on nearby joint or bone for other causes. Lesions in small bones of hands and feet when present for a long duration or associated with trauma may present with pain and swelling.
MRI followed by a biopsy (when indicated for an active lesion) are crucial in confirming a diagnosis of enchondroma, and also helping to differentiate between a benign enchondroma versus aggressive chondrosarcoma. A CT scan or in some cases of doubtful aggressive features on imaging (i.e: lesion > 5 cm in dimension, presence of endosteal scalloping, cortical breach etc), a whole body FDG PET CT scan can be performed. Recent reports have identified the role of pet ct in identifying an aggressive chondroid neoplasm, with SUV MAx of 2.0 or less indicative of an enchondroma.
Pathological fracture is rare and they tend to heal conservatively. Increased pain and swelling not correlating with lesion can give suspicion to malignant transformation.
What are treatment options for enchondroma?
Natural history of most enchondromas is to remain asymptomatic. If symptomatic, enchondroma can be treated by Curettage with or without bone grafts and substitutes. Local recurrence is uncommon. Occurrence of local recurrence after treating a primary enchondroma can give rise to suspicion of chondrosarcoma (Grade I or 2). Doubtful lesions undergo an MRI in addition to plain radiograph.
Aggressive lesions or malignant transformed lesions can present with surrounding bone destruction and alteration in bone architecture.
Biopsy (Needle) can be performed is such situations to confirm diagnosis.