Knee pain: a cautionary tale of lipoma arborescens.

We report a case of a 51-year-old man, presenting with non-specific symptoms of unilateral knee pain and swelling, who had experienced a 1-year period of multiple misdiagnoses. He was finally diagnosed with lipoma arborescens only after a MRI of the knee was performed, with postoperative histological confirmation after treatment with joint replacement surgery. The possible pathophysiology, diagnostic modalities and treatment of lipoma arborescens are discussed. The authors hope that our experience with this rare condition can be of learning value to fellow clinicians who frequently encounter patients with arthritis, as an accurate diagnosis and management of lipoma arborescens can give rise to a better clinical outcome for the patient. 2016 BMJ Publishing Group Ltd.