Gigantism, also spelled giantism, is a (usually) deadly illness that is caused by an enlargement or a tumor of the pituitary gland. It starts in childhood or adolescence and results in extreme height. However, if the same illness starts in an adult, or worse, continues from the childhood illness, a freakier condition called acromegaly is the result. If you want to know what that looks like, look at Andre the Giant. For this reason, the phrase "giant little boy" is NOT an oxymoron.