Spontaneous regression of nonfunctioning pituitary adenoma.

Eighty percent of pituitary macroadenomas are nonfunctioning and may be treated conservatively. Spontaneous regression occurs but is rare and generally has an identifiable cause such as chemotherapy, pituitary apoplexy and viral infections. We present a 28 year-old male with a nonfunctioning pituitary macroadenoma that regressed over one year without any apparent cause.