Intra-articular lipoma arborescens of the knee: A report of two cases with bilateral localization

INTRODUCTION: Lipoma arborescens is a very rare pseudo-tumoral lesion of unknown etiology, characterized by lipomatous infiltration of subsynovial stroma, bilateral involvement is exceptional, only eight cases are reported in the literature. PRESENTATION OF CASE: We report the very rare case of two men presented at our department with complaints of swelling of both knees and intermittent joint effusion, Surgical biopsy revealed Lipoma arborescens in both cases. Open total synovectomy was performed. Follow-up evaluation showed no signs of recurrence. DISCUSSION AND CONCLUSION: Lipoma arborescens is a rare entity, the unilateral form affecting the knee is the most common, with a predilection for suprapellar recess. Magnetic resonance imaging (MRI) is the examination of choice showing multiple villous proliferation of the synovium and fat-like cells, with a fatty signal on all sequences. Treatment by open or arthroscopic synovectomy offers the best outcomes.