Refractory knee giant cell tumor of the synovial membrane treated with intra-articular injection of Infliximab: a case series and review of the literature.

Giant cell tumor (GCT) of the synovial membrane, also known as pigmented villonodular synovitis, causes a progressive, relapsing and destructive arthropathy affecting one or more synovial joints. Systemic therapy can be combined to intra-articular treatments, including surgical synoviectomy, especially when monoarticular. Despite that, the synovial membrane commonly grows again with clinical relapse. Here, we report three case of patients diagnosed with GCT of the knee who had an early relapse of the disease even after surgical synoviectomy. All of them underwent intra-articular therapy with infliximab and subsequent synoviectomy to eradicate residual tissue. A complete remission of CGT was achieved without relapse occurring during the follow-up. These preliminary data need to be confirmed by further clinical trials; however, intra-articular therapy with infliximab might be deemed a potential option to treat CGT of a single joint.