Keywords

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Definition: Benign cartilage neoplasm originating at the surface of the bone.

Rather rare, it is usually observed in children or young adults. It prefers the metaphyses of the long bones, particularly the proximal humerus. It is usually slightly to moderately painful because of nociception by the periosteum and commonly causes some swelling. Imaging shows a superficial erosion of the bone cortex, at times slightly scalloped, with regular borders. Such erosion is caused by a hemispherical periosteal cartilaginous mass, usually of small to moderate size. In the larger chondromas, tumor often contains granular or popcorn densities.

figure a

Histologically the tumor is very similar to enchondroma, but it more frequently displays features of cell proliferation (high cellularity, nuclear plumpness, and frequent double-nucleated cells). Being somewhat painful and causing some swelling in most instances, it usually requires surgical management consisting of either en bloc marginal excision or thorough curettage, equally effective.

FormalPara Key Points

Clinical

Some pain, young patients

Radiological

Subperiosteal, metaphyseal, with erosion of the cortex, granular calcifications

Histological

Lobules of benign cartilage. Possible hypercellularity

Differential diagnosis

Periosteal chondrosarcoma

figure b

Male, 22 years old. Small (less than 3 cm) well-circumscribed lobulated lesion composed of hyaline cartilage. The lesion is beneath the periosteum with a sharp margin with the underlying cortex. The chondrocytes frequently are enlarged and hyperchromatic with increased cellularity and variability in nuclear size and shape. Out of context, these features suggest the diagnosis of chondrosarcoma