CSF1R and tenosynovial giant cell tumor: Because PVNS, or tenosynovial giant cell tumor (TGCT), has characteristic cytogenetic abnormalities resulting in the overexpression of colony stimulating factor 1 (CSF1), systemic medication targeting the CSF1/CSF1R axis (imatinib, nilotinib, emactuzumab, and PLX3397) has been proposed in patients with diffuse, relapsed, or multifocal PVNS/TGCT [40].