Teaching Case

A 26 year-old male patient referred with bitemporal hemianopia.

A 26 year-old male patient referred with bitemporal hemianopia. MRI study of the cranium, especially of the sellar area and optic pathways was ordered. MRI study was performed on a 1.5 T MR scanner, with SE T1, FSE T2, post-gadolinium SE T1 weighted sequences on three planes. A mass lesion of the sellar-suprasellar area was detected.

Pituitary adenomas are common intracranial neoplasms, accounting for approximately 10 % of all primary intracranial neoplasms, and between one third and one half of all sellar and juxtasellar masses. Seventy to eighty percent of pituitary adenomas are macroadenomas according to the imaging based studies, which are adenomas larger than 10 mm in size. Macroadenomas are seen in all ages, most commonly in between 25-60 year old. The females are affected more than males. Macroadenomas are usually endocrinologically inactive. Clinical signs and symptoms usually depend on the mass effect such as hypopituitarism (due to compression on the neighboring hypophyseal tissue and on the infundibulum), bitemporal hemianopia (with superior extension), pituitary apoplexy, hydrocephalus, cranial nerve involvement (most commonly third, fourth and sixth cranial nerves). In imaging studies the tumor has a figure eight appearance with suprasellar component. Macroadenomas extend into the neighboring areas such as suprasellar cistern, cavernous sinus, sphenoid sinus, and nasopharynx in up to 67 % of the cases in imaging based studies. During the carotid sinus invasion it may encase the carotid artery as well. Tumoral necrosis, cysts, and hemorrhagic foci are common. On computed tomography the tumor is isodense to brain tissue with infrequent calcifications ( 1-8 %), it may erode the bony floor, and it enhances intensely with iodinated contrast material. On MRI macroadenomas are usually isointense with cortical gray matter, and enhance intensely with gadolinium containing contrast materials. However they may show variable signal intensity patterns depending on the necrotic, cystic or hemorrhagic components. Craniopharyngioma, suprasellar meningioma, metastasis, pituitary granulomatous infiltrations, and pituitary abscess may simulate the appearance of macroadenomas, but both imaging and clinical findings help us to make the differential diagnosis. Some complications may develop secondary to the macroadenomas, such as obstructive hydrocephalus, encasement of carotid artery, and rarely pituitary apoplexy. Treatment is surgical resection of the tumoral mass.