Governor Pio Pico, the monster of California…no more: lessons in neuroendocrinology

We hypothesize that Pio Pico, the last Mexican Governor of California, had acromegaly between at least ages 43 to 57, from 1844 to 1858, before Pierre Marie published the clinical description of acromegaly in 1886. Pico’s probable growth hormone-secreting pituitary tumor likely infarcted spontaneously after 1858. The tumor infarction resulted in burnt-out acromegaly and probably restored normal pituitary function. Pearce Bailey published the first account of pituitary tumor infarction only in 1898. Pico’s undiagnosed, misunderstood, profoundly acromegalic appearance was widely misinterpreted, leading to pervasive, degrading, and highly prejudicial comments. This landmark case study in neuroendocrinology provides the opportunity to re-examine elements of 19th century California and American history.