Lipoma arborescens successfully treated with (90)Y synovectomy.

Lipoma arborescens (LA) in the knee is a benign intra-articular lipomatous proliferation of the synovial membrane, and data on treatment of LA by radionuclide therapy is sparse. We present a rare case of bilateral LA in the knees successfully treated with injection of Y-citrate colloid. We assessed the biodistribution of the radiopharmaceutical through the use of SPECT/CT imaging. Our images show slight redistribution of the radiocolloid in the knee joint, whereas most of the radioactivity remains localized around the LA. MRI scans confirmed the efficacy of this treatment, with a significant reduction in LA volume after 6 months.