Chondroblastoma is a benign bone tumor typically seen in which population and location?

• A. Malignant bone tumor in adults
• B. Benign tumor in patients under 20 located in the diaphysis
• C. Benign bone tumor under 20 located in the epiphysis/metaphysis
• D. Infectious osteomyelitis

Answer: (C)

Chondroblastoma is a benign cartilage-producing tumor that classically affects adolescents and arises at the end of long bones near the joint—the epiphysis (often with some metaphyseal involvement). This combination—age under 20 and epiphyseal/metaphyseal location—fits best. It is not a malignant tumor, not typically located in the diaphysis (the shaft), and it is not an infectious osteomyelitis.