Age:in adolescents or young adults;

Location:Metaphyseal and central.

Bone destruction pattern:Geographic type1 b.

Tumor matrix pattern:coarse dot-like, popcorn-like mineralization of chondroid matrix.

Periosteal reaction:not present.

D.D. according to location

-Fibrous dysplasia.

-Enchondroma.

-Simple bone cyst.

-Pyogenic osteomyelitis.

Diagnosis:Characteristic appearance of enchondroma of long bone(most common site is proximal hemerus).