Ectopic Hypothalamic and Pituitary Hormone Secreting Syndromes

Recognition of the ectopic hormone secretion outside the primary hormone glands and tissues extends to early decades of the 20th century. Although several theories have been proposed for this entity, collection of secretory cells possessing the properties of amine precursor uptake and decarboxylation in some tissues and tumors have been the most justified proposal. As none of these theories completely provides a satisfactory explanation, roles played by more than 1 mechanism in the scenario are also probable. The ectopic production and secretion of corticotropin-releasing hormone, growth hormone-releasing hormone, gonadotropin-releasing hormone, adrenocorticotropic hormone, prolactin, growth hormone, follicle-stimulating hormone, and luteinizing hormone have all been demonstrated in the tumors, as well as in the hyperplastic and chronic inflammatory tissues outside the endocrine system. This review article focuses on the current available information on ectopic hypothalamic and pituitary hormone secreting syndromes, which may be beneficial for neurosurgeons.