A case of ectopic pituitary adenoma occurring in the sphenoid sinus

Ectopic pituitary adenomas are relatively rare tumors. We present a case of ectopic pituitary adenoma occurring in the sphenoid sinus. A 63-year-old woman was referred to our hospital complaining of headache. She had no endocrinological abnormalities. Magnetic resonance imaging showed a tumor in the sphenoid sinus, adjacent to the sellar floor and appearing as a low-signal on T1-weighted image and a high signal on T2-weighted image. No connection between the normal pituitary gland and tumor was observed. Using an endonasal-transsphenoidal approach assisted with neuro-endoscopy, we performed total removal of the tumor. No connection between the normal pituitary gland and the tumor was found. Histopathological analysis showed a pituitary adenoma. As demonstrated by our case report, differential diagnosis of a tumor occurring in the sphenoid sinus must include consideration of the existence of an ectopic pituitary adenoma.