Final answer:
An osteochondroma is a benign bone tumor that usually forms within the epiphysis of long bones. It is the most common type of benign bone tumor.
Step-by-step explanation:
A benign bone tumor that usually forms within the epiphysis of long bones is called an osteochondroma. It is the most common type of benign bone tumor, accounting for approximately 35% of all bone tumors.
An osteochondroma forms from cartilage that is overactive during the growth period, resulting in the growth of a bony projection from the surface of the bone. The tumor typically appears as a mushroom-shaped formation with a bony stalk that attaches to the underlying bone. It is usually painless and does not grow rapidly.
Diagnostic imaging techniques such as X-ray, CT scan, or MRI may be used to confirm the presence of an osteochondroma and determine its characteristics.