Pituitary enlargement following ipilimumab without long term endocrine dysfunction

Ipilimumab, a monoclonal antibody against CTLA-4, is used in the treatment of melanoma and renal cell cancer. Hypophysitis is one of the more common adverse events, usually presenting with headache, pituitary enlargement and hypopituitarism, mostly ACTH deficiency, which is usually permanent. We describe a series of 3 cases developing pituitary enlargement in keeping with hypophysitis after ipilimumab without any long-term pituitary hormone deficiencies. This illustrates that a comprehensive endocrine assessment is required even when pituitary enlargement is present.