Lipoma Arborescens of the Knee: Report of Three Cases and Review of the Literature

Figure 2

MR images on coronal T1-weighted (a), sagittal PD-weighted with fat saturation (FS) (b), and axial, sagittal, and coronal T1-weighted with FS after iv administration of gadolinium (c), (d), and (e), respectively, depict frond-like villi projecting inwards from the synovium with signal equal to fat on all imaging sequences (short arrows). After iv administration of gadolinium, enhancement of the overlying synovium is observed (long arrows), but no enhancement of the underlying fat is detected. Joint effusion is present distending the joint capsule, without any sign of menisci or ligaments’ injury, or osseous erosions.

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