Pituitary adenomas in childhood and adolescence.

Scientific advances are revealing the complexity of pituitary development, which is controlled by multiple transcription factors and signaling molecules. Unregulated pituitary cell growth, resulting in pituitary adenoma, is usually sporadic and results from monoclonal expansion of a single mutated cell. However, some adenomas develop as part of a genetic syndrome. Prolactinoma is the most common hormonally active pituitary adenoma in children. The non-functioning (non-secreting) pituitary adenoma is the second most common and often stains positive for GH, PRL, and/or TSH. While Cushing disease, resulting from an ACTH-secreting adenoma, commonly manifests as weight gain with growth deceleration in children, GH excess causes gigantism with rapid, accelerated growth inappropriate for the height of the family. TSH secreting pituitary adenomas are rare, and biochemical analysis will show an elevated thyroxine level with a non-suppressed or high TSH. Though the natural history of pituitary incidentalomas in children is unknown, adult practice guidelines are established.