CSF1R and tenosynovial giant cell tumor: Clinical CSF1R inhibition is an effective therapeutic principle in the treatment of a rare benign tumor, tenosynovial giant cell tumor (TGCT), which is characterized by aberrant CSF-1 secretion and the recruitment of CSF1R dependent inflammatory cells which dominate this tumor [162,163], and a small molecule CSF1R inhibitor, pexidartinib, has been approved for this indication.