Clinically Nonfunctioning Pituitary Tumor

Craniopharyngiomas are typically slow growing with slow onset of symptoms. Visual deficits are a common complaint due to direct pressure of the tumor on the optic chiasm. Hormonal abnormalities can occur with compression of normal pituitary structures. In children, growth failure from hypothyroidism or growth hormone deficiency is the most common presentation, whereas sexual dysfunction is the most common presenting symptom in adults. Other symptoms include headache, depression, and lethargy.

Diagnostic Studies. Magnetic resonance imaging (MRI) has supplanted computed tomography (CT) as the imaging procedure of choice for most sellar masses. On noncontrast images, the normal pituitary gland and pituitary adenomas are isointense to the rest of the brain parenchyma. With dynamic administration of gadolinium contrast, the majority of pituitary adenomas will exhibit early enhancement before the normal gland; when this washes out, the normal pituitary gland will enhance more intensely than the adenoma. Because of the increased risk of associated hormonal dysfunction, a thorough evaluation of the hypothalamic-pituitary axis must be conducted to assess for hormonal excess or deficiency. In those patients in whom the pituitary lesion is discovered incidentally, ophthalmologic and endocrine screening should be performed.

On imaging, craniopharyngiomas typically present as a parasellar mass with calcification and cystic components. In these cases, CT may be the superior diagnostic modality because it highlights calcifications and cystic lesions better than MRI. Occasionally, calcifications are not readily identified on imaging, thus a histologic diagnosis is warranted. Many patients with craniopharyngiomas will have symptoms of hypopituitarism, thus a thorough endocrine evaluation is recommended.

Treatment. The primary treatment for nonfunctioning macroadenomas and most hypersecreting adenomas is trans-sphenoidal surgery. Traditionally, most surgeons enter the sphenoid sinus through a variant of the transseptal approach, which exposes the anterior wall of the sphenoid bone. After the removal of the anterior wall, the bony floor of the sella turcica is removed, and the sella dura is then opened to allow for tumor removal. The most important aspect of the surgery is the preservation of the arachnoid membrane. Low postoperative morbidity depends on preventing blood from entering the cerebrospinal fluid (CSF) during the operation and leakage of CSF postoperatively. Afterward, the muscle is placed in the tumor cavity, occasionally with a piece of nasal cartilage. The mucosal flaps are reapproximated and the nose is packed.

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