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).:100:245Common symptoms of TGCT include swelling, pain, stiffness and reduced mobility in the affected joint or limb.:102 This group of tumors can be divided into different subsets according to their site, growth pattern, and prognosis.:361 Localized TGCT is sometimes referred to as giant cell tumor of the tendon sheath;:100 diffuse TGCT is also called pigmented villonodular synovitis (PVNS).:102
Classification
Classification for TGCT encompasses two subtypes that can be divided according to site – within a joint (intra-articular) or outside of the joint (extra-articular) – and growth pattern (localized or diffuse) of the tumor(s).:100:361 Localized and diffuse subsets of TGCT differ in their prognosis, clinical presentation, and biological behavior, but share a similar manner of disease development.:100
Localized TGCT
Localized TGCT is sometimes referred to as localized pigmented villonodular synovitis (L-PVNS), giant cell tumor of the tendon sheath (GCT-TS), nodular tenosynovitis, localized nodular tenosynovitis, and L-TGCT.:1:100The localized form of TGCT is more common.:100:245 Localized TGCT tumors are typically 0.5 cm-4 cm),:101 develop over years,:100 are benign and non-destructive to the surrounding tissue, and may reoccur in the affected area.:101 The most common symptom is painless swelling.:101 Localized TGCT most often occurs in fingers, but can also occur in other joints. [Source: Wikipedia 
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