Synovial Lipomatosis; A Clinicopathological Study of a Rare Entity

Objective: This study was conducted to analyse the clinicopathological and radiological features associated with Synovial lipomatosis.Patients and Methods: Cases diagnosed as Synovial lipomatosis from 2008 to 2018 were retrieved and clinical information and histology were reviewed.Results: Thirteen cases of Synovial lipomatosis were diagnosed between 2008 and 2018. Most common site was knee joint and mean age of presentation was 28.6. About 62% of subjects were males and mostly presented with joint pain and swelling. Two of the subjects had significant history of trauma and disease was bilateral in one of the cases. Microscopically, villous proliferation of synovium with infiltration of mature adipocytes was noted. Focal synovial hyperplasia and inflammatory infiltrate were other findings in some of the cases.Conclusion: Synovial lipomatosis should be considered in the differential diagnosis of joint pain and swelling and should be distinguished from Pigmented villonodular synovitis, Synovial haemangioma and intra-articular synovial lipoma (IASL) using radiological and histological features.

Results of Arthroscopic Synovectomy for Treatment of Synovial Lipomatosis (Lipoma Arborescens) of the Knee

Synovial lipomatosis (SL; lipoma arborescens) is a tumor-like condition with villous proliferation of the synovium. The exact etiology of SL is still unknown. The knee is the most commonly involved part. The goal of this retrospective study was to report the results of arthroscopic synovectomy in patients with SL in their knee joints as well as to emphasize the importance of considering this pathology when treating patients with recurrent knee joint effusions. In total, 21 patients (8 females and 13 males) were evaluated retrospectively from May 2009 to July 2014. The mean follow-up period was 29.13 (range, 12–61) months. The mean duration of compliance was 22.76 (range, 7–61) months. All patients were evaluated by Knee Society score pre- and postoperatively. The mean preoperative and last follow-up Knee Society scores were 67.82 and 88.23 points, respectively. There was a significant difference between the preoperative and postoperative Knee Society scores (p = 0.0001). Histopathological examinations showed that the subsynovial layer exhibited diffuse replacement by mature fat cells that had formed villous projections. In addition, infiltration of mononuclear inflammatory cells was observed at different stages. SL is a nondestructive and benign tumor pathology of the knee joint without a clearly identified etiology. The main difficulty in diagnosis is lack of clinical practice.

Synovial Lipomatosis of the Glenohumeral Joint

Synovial lipomatosis (also known as lipoma arborescens) is a rare and benign lesion affecting synovium-lined cavities. It is characterized by hyperplasia of mature fat tissue in the subsynovial layer. Although the most commonly affected site is the knee joint, rarely additional locations such as tendon sheath and other joints are involved. We present a case of synovial lipomatosis of the glenohumeral joint in a 44-year-old man. The clinical data radiological studies and histopathologic results are described, as well as a review of the current literature.