Osteochondroma (Radiograph)

Frontal radiograph of the right shoulder shows a broad-based exostosis with continuity of bone cortex and medullary marrow to the metaphysis of the humerus.

This is a classic radiographic appearance of 'sessile osteochondroma' at the most common location (metaphysis) of bone.


Facts:
Most common benign bone tumor

Due to aberrant epiphyseal development

Growth stops after skeletal maturation

Malignant transformation in 1-2% of solitary lesion



Points:
Suspect malignant transformation if: growth after skeletal maturation, pain in the absence of fracture, bursitis or nerve compression

MRI and CT to demonstrate thickness of cartilaginous cap, if >2 cm suspect malignancy

Reference:
Stoller et al. Diagnostic Imaging: Orthopedics. 2004

Image Courtesy of RadiologyinThai.com