Advances in treatment for tenosynovial giant cell tumors

Introduction: Tenosynovial giant cell tumor (TGCT) is a benign clonal neoplastic proliferation arising from the synovium often causing pain, swelling, joint stiffness, and reduced quality of life. The optimal treatment strategy in patients with diffuse-type TGCT (dt-TGCT) is unclear. The purpose of this review is to describe recent advances in the knowledge of TGCT pathogenesis and potential therapeutic implications. Areas covered: Current treatment options for TGCT are discussed, including surgery and radiotherapy. Recent evidence that TGCT cells overexpress colony-stimulating factor 1 (CSF1), resulting in recruitment of CSF1 receptor (CSF1R) positive tumor-associated macrophage and contributing to tumor growth, has created new opportunities for systemic treatments of dt-TGCT. Results of clinical trials with CSF1R inhibitors are now available. These inhibitors include small molecules such as imatinib, nilotinib, pexidartinib, and monoclonal antibodies like emactuzumab, MCS110, and cabiralzumab. Expert opinion: TGCT impairs patients’ quality of life significantly. The confirmation that the pathogenetic loop of TGCT can be inhibited through targeted agents could potentially change the therapeutic armamentarium for this condition.