Pituitary Tumors—Cinical Presentation Syndromes
Some clincal nuts and bolts of pituitary tumors.
Pituitary tumors present in two general ways:
are becoming better recognized clinically and more easily detected due to increasingly sensitive laboratory tests. Typical hormonal syndromes include:
Local mass effect
occurs when the pituitary tumor either does not secrete active hormone, or when the effects of hormone hypersecretion are not recognized. The tumor simply grows, slowly but inexorably, until it impinges on surrounding structures, causing:
Tumors which present this way are commonly nonsecreting tumors and prolactinomas in older men.
Pituitary apoplexy is a rare presentation of pituitary tumor (but like that Force 10 gale, it's the one that you remember...). People presenting with apoplexy are sick.
A pre-existing (and usually undiagnosed) pituitary macroadenoma either infarcts and swells or bleeds acutely. The sudden doubling or tripling of the pituitary tumor's volume impinges on its surrounding structures and causes the characteristic findings of pituitary apoplexy. Sudden pressure on the optic nerves causes decreased vision, up to total blindness. Sudden pressure on the cranial nerves in the cavernous sinus cause diplopia. Sudden pressure on the pituitary gland cause pituitary shutdown and potentially lethal Addisonian crisis (lack of cortisol). Leakage of blood into the subarachnoid space causes unconsiousness and meningeal irritation.
Physical examination—PE in pituitary apoplexy shows a hypotensive patient, often with impaired consciousness, who may have signs of nuchal rigidity, photophobia, nausea and vomiting. All this is also consistent with SUBARACHNOID HEMORRHAGE.
Laboratory testing—Acutely is pretty inconclusive. Electrolytes are usually OK, WBC may be slightly elevated. Serum cortisols are low (but they usually can't be gotten stat).
Radiology—Is diagnostic. CT scanning usually reveals a lesion in the sellar area with or without subarachnoid blood. MR scanning can delineate this lesion exquisitely. If there is any question, get a stat MR of the sellar area looking for a large macroadenoma. If these studies are negative, consider lumbar puncture to diagnose subarachnoid hemorrhage and a cerebral angiogram to look for an aneurysm (cause of 90% of nontraumatic subarachnoid hemorrhage).
Treatment—THIS IS A NEUROSURGICAL EMERGENCY!
Nomenclature for discussing pituitary tumor size
There are a variety of proposed systems for naming pituitary tumors, based on size, location of invasion of surrounding structures, extent of invasion of surrounding structures, etc. We will ignore these systems for now.
MR imaging of pituitary tumors
Let's face it, technology works. MR imaging is the test of choice for diagnosing and planning treatment of pituitary tumors. The surrounding bone, which obscures CT scanning, disappears. The soft tissue of the pituitary gland, tumor, and surrounding structures is displayed with exquisite detail. Variations in MR imaging can elucidate even very small pituitary tumors. Examples of MR imaging in pituitary tumors follow: