Enchondroma

• 2nd-4th decade
• M=F
• Intramedullary neoplasm
• Lobules of benign hyaline cartilage
• Second most common benign chondral lesion after osteochondroma
• Tubular bones of hands and feet
• Asymptomatic, present when size increases or when pathological fracture occurs
• Proximal phalanges in most cases, then metacarpals, middle phalanges
• Less common in bones of feet, femur, tibia and humerus 
• Enchondroma protuberans – eccentric enchondroma with extra-osseous component, covered by thin shell of intact cortical bone. Fingers or toes. 

Imaging 

• Centrally in phalanges and metacarpals
• Metaphyseal or diaphyseal 
• Eccentric and often solitary
• Well circumscribed, lobular or oval lytic lesions 
• May expand the cortex
• 10 to 50 mm in size
• Chondral-type mineralization may be seen
• MRI – small septa within lesion shows mild enhancement. 

Read more

Melamud, Kira, et al. “Diagnostic imaging of benign and malignant osseous tumors of the fingers.” Radiographics 34.7 (2014): 1954-1967.

Murphey, Mark D., et al. “Enchondroma versus chondrosarcoma in the appendicular skeleton: differentiating features.” Radiographics 18.5 (1998): 1213-1237.