Intra-articular Lipoma of the Knee Joint Located in the Lateral Recess: A Case Report

INTRODUCTION: Lipomas are the most common type of soft-tissue tumor, but intra-articular lipomas are very rare. Most cases occur in the knee joint. This is a report of intra-articular lipoma in the knee joint, 8 months after removal with good post-operative outcome. CASE REPORT: A 56-year-old female who presented soft-tissue mass on her right knee. She felt uncomfortable but not in pain. The mass grew gradually and she wanted to be surgically removed. The mass was too large (5 cm × 4 cm × 2 cm) to be removed endoscopically, so arthrotomy was made. The mass was true lipoma histologically. She is living happily without recurrence after surgery. CONCLUSION: We have described an intra-articular synovial lipoma in the knee of a middle-aged female. Intra-articular lipomas are very rare. The tumor in this case was relatively large but painless, and the chief complaint was discomfort. It grew gradually, so the removal was performed. At present, the patient is living happy without recurrence after surgery.