Addison's disease and ACTH-producing pituitary microadenoma

Abstract

A 28-year-old man diagnosed with primary adrenal insufficiency (Addison's disease) in 2002. Following diagnosis, replacement therapy with hydrocortisone and fludrocortisone was indicated. Hydrocortisone replacement therapy was unsuccessful, and increased ACTH levels as high as 996 pg/dl were observed on outpatient follow-up. A pituitary MRI revealed a pituitary microadenoma. These findings raised three possibilities: (1) treatment is insufficient; (2) there is no relationship between Addison's disease and pituitary microadenoma; and (3) the microadenoma is similar to Nelson's syndrome. This latter is the most satisfactory explanation of this patient's clinical picture.

Keywords

• Nelson's syndrome
• ACTH
• Addison's disease
• Autoimmune adrenalitis