Apoplexy in pituitary microadenomas

Pituitary apoplexy is a clinical syndrome of hemorrhage or infarction of a pituitary adenoma. It has classically been associated with pituitary macroadenomas. The authors report three cases of pituitary apoplexy that occurred in patients with pituitary microadenomas. The presentation, endocrine results, and radiological and clinical outcome of each patient are described. In each of these cases of pituitary apoplexy due to microadenoma, the presenting headache was mistakenly attributed to a different diagnosis. The authors propose that pituitary apoplexy associated with a microadenoma may be much more common than appreciated and could be misdiagnosed as headache of alternative cause. Clinicians and radiologists should be aware of this clinical presentation.