<b>Conclusions</b>: Apart from the well-known osteoclastogenesis factor CSF1, inflammatory cytokines (TNF-α and IL-1β) and monocyte-macrophage lineage makers (CD68, CD163) are signalling pathways key to TGCT disease progression and associated bone destruction. This evidence concerns the gene CD68 and tenosynovial giant cell tumor, diffuse type.