Diffuse tenosynovial giant cell tumor of knee with largest loose body: A rare case report

Abstract

Background: Tenosynovial Giant Cell Tumor (TGCT), also known as Pigmented Villonodular Synovitis (PVNS), is a rare, benign yet locally aggressive tumor affecting the synovium of joints, most commonly the knee. It exists in localized and diffuse forms, with the diffuse type being more extensive and associated with higher recurrence rates. Presentation with large intra-articular loose bodies is exceedingly uncommon.Case Presentation: We report a rare case of diffuse TGCT in a 58-year-old male presenting with a 3-month history of knee pain, swelling, and locking. Clinical examination revealed palpable loose bodies and restricted range of motion. Imaging showed multiple calcified loose bodies in the suprapatellar and lateral parapatellar areas of the right knee. Arthrotomy revealed multiple loose bodies, with the largest measuring 7×5×2.5 cm—one of the largest reported in literature in the context of TGCT. Histopathological examination confirmed the diagnosis of diffuse TGCT, showing hemosiderin-laden monocytes, foam cells, and multinucleated giant cells.Management and Outcome: Complete open synovectomy was performed, resulting in improved range of motion from 90° to 140° intraoperatively. The patient was mobilized on postoperative day one and remained symptom-free at one-month follow-up.Conclusion: Diffuse TGCT with giant loose bodies is a rare presentation that may mimic synovial chondromatosis. This case highlights the importance of thorough evaluation and surgical management in atypical presentations of knee joint pathology. To our knowledge, this represents one of the largest TGCT-associated intra-articular loose bodies reported to date.