Giant is a person who grows abnormally tall because of a disorder in the pituitary gland. This condition, called gigantism, can cause people to grow as tall as 9 feet (274 centimeters). Many individuals are excessively tall because of an inherited trait, but physicians do not consider them giants.
The growth of human bones is regulated by a hormone called growth hormone (GH), which is secreted by the pituitary. During childhood, GH causes a thickening of the epiphyseal cartilage, a plate of soft tissue near the ends of the bones. This cartilage develops through the years and is absorbed by new layers of bone tissue. The continued absorption of cartilage increases the length of the bones. Gigantism occurs when the pituitary secretes excessive GH, increasing the growth of epiphyseal cartilage. In some cases, this malfunction is caused by a pituitary tumor.
A person stops growing after all epiphyseal cartilage has been absorbed by the bones–usually between the ages of 18 and 24. When this occurs, GH can no longer increase height, but excessive amounts of it may cause acromegaly. This condition produces overgrowths in the bones of the face, feet, and hands. Many cases of acromegaly are caused by a pituitary tumor and occur in people of normal height.
If treatment begins during childhood, gigantism can be controlled by decreasing the activity of the pituitary gland with radiation treatment. In some cases, pituitary tumors are removed surgically. The surgeon may reach the tumor through the nasal cavity, cutting through the floor of the cranium to get to the pituitary. The patient has no apparent scar after such surgery.
