Acromegaly due to an ectopic pituitary adenoma in the sphenoid sinus.

An ectopic pituitary adenoma, exclusively involving the sphenoid sinus, associated with a normal size pituitary gland and an empty sella is a rare clinical entity. Only four cases have been found in the literature. We describe the case of a 47-year-old woman with clinical and biochemical acromegaly. Computed tomography (CT) appeared to show expansion of the sellar floor inferiorly into the sphenoid sinus, and magnetic resonance imaging (MRI) demonstrated an empty sella and a mass lesion confined to the sphenoid sinus. The tumor was totally resected by taking a transnasal endoscopic approach and the dura mater of the base of the pituitary fossa was confirmed intact.