Autoimmune attack of the pituitary gland resulting in reduced hormone production was first discovered as a result of an autopsy in 1962. The autopsy described destruction of the pituitary and thyroid consistent with autoimmune attack and included atrophy of the adrenal glands. As Magnetic Resonance Imaging became more available diagnosis increased dramatically. At this time it is believed that the disease is far more prevalent than is diagnosed. Nevertheless, autoimmune hypophysitis is frequently referred to as a rare disease and the most recent estimates as to its prevalence give it a value of around 5 per million.