Autoimmune (lymphocytic) hypophysitis is a rare disease that should be considered in the differential diagnosis of any nonsecreting pituitary mass, especially when occurring during pregnancy or postpartum. We have analyzed 370 articles published from January 1962 to October 2004 and identified a total of 379 patients with primary lymphocytic hypophysitis. The present review synthesizes the clinical and research data reported in this body of scientific literature.