Lipoma Arborescens: can we afford to miss it?

Lipoma Arborescens is an extremely rare, benign lesion effecting the synovial tissue of joints. It is characterized by villous lipomatous proliferation of the synovial tissue. The aim of our study was to evaluate its diagnostic features and analyse the functional outcome of arthroscopic management.

We studied 13 patients who were diagnosed to have lipoma arborescens at our institution during the period from October 2005 to October 2019. All patients underwent arthroscopic synovectomy. Histopathological examination confirmed the diagnosis. Pre-operative and post-operative functional assessment was done using Tegner Lysholm score.

Mean age was 46.6 years. All patients presented with progressive swelling of knee joint, while 6 patients also complained of pain. Average duration of symptoms was 34 months. All the patients were diagnosed based on MRI findings. Tegner Lysholm scoring at last follow up visit, had 11 patients with excellent outcome, 1 patient with good outcome, and 1 patient with fair outcome. None of the patients had recurrence, nor underwent any subsequent procedure of the operated joint.

Lipoma arborescens is a rare condition which should be a differential in patients with mono-articular swelling of the knee joint, and can be confirmed with MRI. It should not be misdiagnosed or missed at early stages as prolonged duration of symptoms and delay in treatment is likely to lead to development of secondary arthritis of the joint. Arthroscopic synovectomy showed good functional outcome and no recurrence.