Spontaneous recovery from pathologically confirmed lymphocytic adenohypophysitis with a dramatic reduction of hypophyseal size

A pituitary mass compressing the optic nerve was revealed by magnetic reson ance imaging (MRI) in a 35-year-old woman complaining of visual disturbance in the post-partum period. Responses of plasma gonadotropin and corticotro pin-cortisol levels to respective hypothalamic hormones were delayed or blu nted, but the response of plasma prolactin to thyrotopin-releasing hormone was exaggerated. Diabetes insipidus was not associated. Biopsy revealed lym phocytic adenohypophysitis, and no hypophysectomy was performed. Only five weeks later, the pituitary mass spontaneously disappeared on MRI. The pitui tary function was normalized. Anti-thyroidal and anti-pituitary antibodies were negative throughout the clinical course. Pituitary masses developing d uring late pregnancy or the post-partum period should be carefully observed .