Presentation
Ankle pain
Patient Data
Sagittal Oblique T1-weighted MRI of the ankle shows a low signal intensity lesion in the calcaneus surrounded by a high signal intensity area.
Sagittal Oblique T2-weighted image depicts both compartments of the lesion with intermediate signal intensity. There is misregistration artifact at the boundaries of two counterparts.
Sagittal Oblique fat suppressed sequences completely suppressed the surrounding counterpart, proving it to be fatty tissue. The central counterpart is hyper-intense that is compatible with a cystic lesion.
Case Discussion
The presence of a fat-containing lesion within the calcaneus represents intraosseous lipoma. The presence of cystic components suggests involuting lipoma.
Chemical shift artifact are produced at water-lipid interfaces and present with white or black lines at the interface. These artifacts are most commonly seen when a cystic structure is surrounded by fatty tissue. This case nicely presents the chemical shift artifact at the boundary of a water-containing lesion sorrounded by fat.