This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Giant cell tumor of tendon sheath is - 
Select and explain. 
A. Traumatic, B. Infective, C. Malignant tumor, D. Benign tumor
D: Benign tumor
Answer: D: Benign tumor 
Explanation: It is also known as giant-cell synovioma and localized nodular tenosynovitis.
They are the second most common benign tumor of the hand.
They most commonly occur in patients aged 30-50 years.
They are associated with degenerative joint disease.
Typically, these masses occur along the volar aspect of the hand and fingers and are most commonly adjacent to the DIP joint.
Surgery to remove the tumor is a common treatment, though the tumor may recur.