Distal defect of the humerus, a possible normal variant: a case report.

BACKGROUND

Many normal variants of bones on plain radiographs have been reported.

CASE PRESENTATION: In the current report, a 14-year-old Asian girl noticed an occasional slight elbow pain. She had no traumatic episode. Plain radiographs showed a well-defined osteolytic lesion with a sclerotic rim, which was continuous with the normal subarticular bone in the distal humerus. Magnetic resonance imaging revealed that the defect area seen on the plain radiograph showed low-signal to iso-signal intensity on T1-weighted images and slightly high-signal intensity on T2-weighted fat suppression images. Bone edema was not observed. The association between her elbow pain and the lesion was not conclusive.

CONCLUSIONS

The findings from the images suggested that the lesion was a normal variant rather than osteochondritis dissecans or a neoplastic lesion, and possibly an anatomical counterpart of a dorsal defect of the patella.