Villonodular synovitis is a type of synovial swelling. Types include: * Pigmented villonodular synovitis *

Giant cell tumor of the tendon sheath Tenosynovial giant cell tumor (TGCT) is a group of rare, typically non-malignant tumors of the joints. TGCT tumors often develop from the lining of joints (also known as synovial tissue). Common symptoms of TGCT include swelling, pain, stiffne ...

Though they have very different names, they have the same histology, and stain positive for

CD68 CD68 ( Cluster of Differentiation 68) is a protein highly expressed by cells in the monocyte lineage (e.g., monocytic phagocytes, osteoclasts), by circulating macrophages, and by tissue macrophages (e.g., Kupffer cells, microglia). Structure a ...

, HAM56, and

vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expresse ...

. They are sometimes discussed together.

References

Inflammatory polyarthropathies {{musculoskeletal-disease-stub