International Journal of Research in Orthopaedics | March-April 2023 | Vol 9 | Issue 2 Page 454 International Journal of Research in Orthopaedics Wankhede AK et al. Int J Res Orthop. 2023 Mar;9(2):454-457 http://www.ijoro.org Case Report Synovial lipoma of the ankle and foot: a rare case report Aniket K. Wankhede*, Rohit Rathod, Girish Mote, C. M. Badole, Mrigank Medhi INTRODUCTION Synovial lipomatosis is a highly rare and uncommon condition of the synovial joints and synovial sheaths and bursae. The etiology of this condition is not completely defined, it has been characterized as the hyperplasia of the adipocytes in the subsynovial layer. 1 The most commonly reported site is the knee joint like the suprapatellar pouch due to the fat pad layer surrounding the knee. 2,3 Occasional reporting of the cases of the elbow, and shoulder is being done. 4-8 Its occurrence in subacromial-subdeltoid bursae and bicipital bursae is also being reported. 5 “Arborescens” in Latin means “tree”, as described tree- like morphology of the lipomatous villous synovial proliferation. When there is the absence of macroscopic villi, then it is termed lipoma simplex or lipoma of the tendon sheath. 9,10 It has been suggested to name both the condition lipoma arborescens and lipoma simplex as synovial lipomatosis. Lipoma involving tendon sheaths of the ankle and foot has rarely been reported in the literature. Here we report a rare case of synovial lipomatosis. CASE REPORT Presenting a case of a 28-year-old male who came to the orthopedic surgeon with 12 years of history of swelling on the dorsum of the right foot which was painless until the last 2-3 weeks. Now suffering from pain in the right foot which aggravates on standing and walking, the patient also complains of a tingling sensation on the fingers of the same foot. There are no skin problems, no morning stiffness, no systemic manifestations, and no other joint involvement. He does not give any history of trauma to the foot recent and in the past. Examination reveals bulky soft rubber-like swelling on the foot, the skin on the swelling is normal. On palpation, the patient has deep tenderness and the dorsalis pedis is not palpable, swelling was compressible. Laboratory routine tests like complete blood count and renal panel are within normal limits, rheumatoid factor ABSTRACT Synovial lipomatosis is an extremely rare type of disease in which there is an excess of adipose tissue involving the synovium layer of joints or synovial sheath around the tendons causing pain, paraesthesia, and weakness. The most common site being reported till now is Knee joint or parapatellar space other joints such as elbows and shoulders are being reported after the knee joint, and the ankle joint is rarely reported 2 cases have been reported in the English literature. We report a case of a 28-year-old male presenting with swelling of the right foot for 12 years and developed symptoms of pain and tingling on the toes for 2-3 weeks. Multiple bony hard lesions were palpated on the base of the foot, ultrasonography (USG) showed a subcutaneous lesion around the extensor tendons of the foot and fine needle aspiration cytology (FNAC) had a picture of the synovial cyst. Surgical excision was done and histopathology was reported to be as a fibrofatty tissue with multiple adipocytes suggesting lipoma arborescent. Keywords: Synovial lipomatosis, Ankle and foot, Lipoma, Lipoma arborescent Department of Orthopaedics, MGIMS Sevagram, Wardha, Maharashtra, India Received: 11 January 2023 Revised: 07 February 2023 Accepted: 13 February 2023 *Correspondence: Dr. Aniket K. Wankhede, E-mail: dr.aniket.w@gmail.com Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: https://dx.doi.org/10.18203/issn.2455-4510.IntJResOrthop20230482