Presentation
Moderately tender mass near the patellar tendon.
Patient Data
Age: 40 years
Gender: Female
From the case:
Pigmented villonodular synovitis of Hoffa's fat pad
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Intermediate signal intensity mass with signal void rim (arrow) due to hemosiderin deposits. It shows muscle isointense signal on T1-weighted images and moderate enhancement after contrast injection.
Case Discussion
Circumscribed 5 mm mass in Hoffa's fat pad with peripheral signal voids due to susceptibility artifacts caused by hemosiderin deposits. The lesion was surgically excised. Histopathologic diagnosis: pigmented villonodular synovitis (PVNS).