Adrenocortical tumors (ACT) are rare. For every 10 million people under 15 around the world, only 3 or 4 have ACT each year. The number of new cases is different in different countries. For every 10 million people, the incidence (how many people learn they have it during a certain time) ranges from 1 per year in Hong Kong to 30-40 in southern Brazil, where doctors have found a cluster of children with ACT. In the United States, there are 25 to 30 new ACT cases every year in children and teenagers.
The average age of children who get ACT is about 3 years old. About 65 percent of patients with ACT are younger than 5 when doctors find it.
ACT can also happen in adults. It is most common in adults in their 40s and 50s. The clinical signs of adult ACT are different from ACT in children.