Diagnostic Considerations
A number of other intracranial neoplasms can present as intrasellar tumors. These include craniopharyngiomas, meningiomas, neurofibromas, ectopic germinomas, and, rarely, metastatic tumors.
Granulomatous and infectious disorders can localize to the sellar region or the hypothalamus (eg, sarcoid, tuberculomas).
Carotid artery aneurysm can occur in the intrasellar region.
Lesions in the sphenoid sinus, such as a mucocele, can mimic the clinical picture of a pituitary adenoma.
Hypothalamus compression can cause increased prolactin levels because of a decrease in the prolactin inhibitory factor. Thus, hyperprolactinemia may be seen with non–prolactin-secreting pituitary adenomas and other sellar lesions with hypothalamic compression.
An unusual postpartum lymphocytic inflammatory pituitary lesion can be associated a mass lesion. This is known as lymphocytic hypophysitis.
Acromegaly can result from a nonpituitary source of increased growth hormone.
Differentiating between Cushing disease and Cushing syndrome, which is related to adrenal hyperplasia or tumor, is important.
Other causes of hyperprolactinemia that are unrelated to mass lesions in the pituitary or the hypothalamus include the following:
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Intracranial - Empty sella syndrome, pseudotumor cerebri, status post cranial irradiation
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Pharmacological - Antipsychotics (and other dopamine receptor antagonists), methyldopa, reserpine, verapamil, estrogen, opiates, cimetidine, sulpiride
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Endocrine - Primary hypothyroidism
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Metabolic - Chronic renal failure, cirrhosis
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Other unusual causes - Breast manipulation, chest wall lesions, spinal cord lesions, stress
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In some cases, a specific cause cannot be established.
Differential Diagnoses
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Dizziness, Vertigo, and Imbalance
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This is a characteristic bitemporal hemianopic visual field defect.
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This contrast-enhanced coronal MRI was obtained in a patient who complained of visual loss.
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This visual field was plotted using a Goldman perimeter (ie, kinetic perimetry). It was obtained from a patient who reported visual loss and had a normal endocrine workup. The dark areas correspond to the impaired peripheral visual field. This visual field defect is consistent with an intrasellar lesion.
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Coronal T1 precontrast MRI A (left panel), B postcontrast (middle panel) and T2 (right panel) showing a sellar mass causing obvious left and upward displacement of the optic chiasm. The mass is a histologically proven pituitary macroadenoma, which presented initially with a large cystic subfrontal extension that was successfully resected in April of 2006. This patient has been observed closely for 2.5 years and despite obvious mass effect, he has no visual complaints and the neuro-ophthalmologic evaluation is normal. Although infrequent, clinicians should be aware of this possibility. Close follow-up is required.
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Axial, sagittal, and coronal MRI of the sellae in a patient with a severe headache, normal neuro-ophthalmologic examination, and no evidence of endocrine failure. A hyperintense mass is observed in the sella with suprasellar extension. This case illustrates the clinical spectrum of pituitary apoplexy. Transsphenoidal resection confirmed the diagnosis of pituitary apoplexy.
