Hypopituitarism associated with transient diabetes insipidus followed by an episode of painless thyroiditis in a young man.

A 16-year-old male complained of a headache and a high fever followed by polyuria. The endocrinological studies showed he had hypopituitarism and central diabetes insipidus, and magnetic resonance imaging (MRI) revealed a pituitary mass. Diabetes insipidus gradually improved and hydrocortisone treatment was begun at three months after onset, but a month later painless thyroiditis developed. An MRI demonstrated a spontaneous shrinkage of the pituitary mass nine months after onset. Lymphocytic hypophysitis followed by painless thyroiditis was the most probable diagnosis, although it is very uncommon especially among men.