Intra-articular osteolipoma of the elbow: A case report and a review of the literature

INTRODUCTION: Lipomas are the most common benign mesenchymal tumors. The intra-articular localization is exceptional. We report the first case of an intra-articular osteolipoma at the elbow. CASE REPORT: A 36-year-old patient with no pathological history, presented to the emergency room with a two weeks history of a painless, progressively left elbow swelling in a context of apyrexia. Physical examination revealed a hot, edematous left elbow. The gentle mobilization of the joint was painless. Biologie was normal. Initial radiograph showed a well-defined lobular image. Ultrasound revealed an anechoic intra-articular collection associated to a synovium hyperaemia and the MRI shows an aspect of synovitis. An arthrotomy was done via an internal approach of the elbow. Joint fluid was red. A free ossified intraarticular mass was discovered. Bacteriological samples were sterile. Histological examination concluded to an osteolipoma with no histological signs of malignancy. At the last 3-year follow-up, the patient didn't report any pain or functional discomfort. Elbow mobility was complete, with the absence of recurrences. DISCUSSION: Osteolipoma is defined as a histological variant of lipoma having undergone bone metaplasia. Allen found 06 cases in a series of 635 lipomas over five years. Pain has not been reported in the literature. In our case the pain was explained by the interposition of the tumoral mass between the articular surfaces. Histological examination confirms the diagnosis and recurrences are rare. CONCLUSION: Osteolipoma is an extremely rare entity of mesenchymal tumors whose intra-articular location, although exceptional, does not worsen the prognosis.