Ectopic pituitary and hypothalamic hormone syndromes.

The pathophysiology and diagnosis of ectopic hormone syndromes are discussed, and a classification of hypothalamic and pituitary ectopic syndromes is provided. Ectopic hypothalamic syndromes resulting from tumor elaboration of GRH, GnRH, CRF, and SRIF and ectopic pituitary hormone hypersecretion of GH, PRL, and TSH are reviewed comprehensively. A practical approach to the clinical work-up and management of these newly described disorders is provided.