Tenosynovial Giant Cell Tumor, Diffuse Type

**Semantic type:** Neoplastic Process

**Definition:** A locally aggressive, diffusely infiltrating tumor, arising in the tendon sheath. It is composed of synovial-like mononuclear cells, hemosiderin-laden macrophages, foam cells, and inflammatory cells. Multinucleated osteoclast-like giant cells are usually present, although in a minority of cases they may be absent or rare. It predominantly affects young adults. Symptoms include joint swelling, pain, and joint effusion.

**Synonyms:** - Diffuse Giant Cell Neoplasm of Tendon Sheath - Diffuse Giant Cell Neoplasm of Tenosynovium - Diffuse Giant Cell Neoplasm of the Tenosynovium - Diffuse Giant Cell Tumor of Tendon Sheath - Diffuse Giant Cell Tumor of Tenosynovium - Diffuse Giant Cell Tumor of the Tenosynovium - Diffuse Tenosynovial Giant Cell Neoplasm - Diffuse Tenosynovial Giant Cell Tumor - Pigmented Villonodular Synovitis