[en] Historical data indicate that pituitary tumors represent 10% of intracranial tumors, while adenomas are noted in approximately 14-23% of normal subjects on autopsy or magnetic resonance imaging (MRI). About 2.5% of these tumors stain positive for GH in histopathologic studies. In contrast, the prevalence of clinically diagnosed acromegaly is lower at 36-69 per million population. Ongoing studies indicate that the actual prevalence of acromegaly in the community may be higher than previous epidemiologic data suggest. Acromegaly can occur both sporadically and in the setting of familial conditions, such as multiple endocrine neoplasia type 1 (MEN1) and Carney complex (CNC). Isolated familial somatotropinoma has been described and newer data suggest that acromegaly may also occur in non-MEN1/CNC families in combination with other pituitary tumor phenotypes.