pituitary area. This understanding requires a working knowledge of radio-logic diagnosis of the most prevalent pituitary diseases, indications for

Endocrinol Metab Clin N Am

37 (2008) 5166surgical intervention, the choice of surgical approach to the lesion, andthe expected extent of resection.

Clinical neuroanatomy of the pituitary

Normal pituitary is approximately 10 to 12 mm in the largest dimension.It is located in the sella turcica and is a part of skull-base structures. Thegland is separated from the suprasellar cistern by a thin diaphragm that ispenetrated by the pituitary stalk. Approximately 10 to 15 mm above thediaphragm lies the optic chiasm, anterior to which are the optic nerves andposterior to which are the optic tracts. Thus, to cause diminution in visualacuity or elds defect, the tumor must expand more than 1 to 1.5 cm abovethe level of the diaphragm and distort the optic pathways.

The sella is bordered laterally by the cavernous sinuses. Each contains thecarotid artery and cranial nerves III, IV, V1, V2, and VI. Impairment of cra-nial nerves III, IV, and VI causes ipsilateral ophthalmoplegia, double vision,ptosis, and dilatation of the pupil. In addition, damage to cranial nerveTreatment of Pituitary Tumors:a Surgical Perspective

William F. Chandler, MDa,b,*, Ariel L. Barkan, MDa,b

aDepartment of Neurosurgery, University of Michigan Medical Center, 3552 Taubman Center,

Box 5338, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USAbDivision of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical

Center, Ann Arbor, MI 48109, USA

This article is intended to provide the clinical endocrinologist with a betterunderstanding of the surgical aspects of diseases aecting the hypothalamic-* Corresponding author. Department of Neurosurgery, University of Michigan Medical

Center, 3552 Taubman Center, Box 5338, 1500 East Medical Center Drive, Ann Arbor,

MI 48109.

E-mail address: wchndlr@med.umich.edu (W.F. Chandler).

0889-8529/08/$ - see front matter 2008 Elsevier Inc. All rights reserved.doi:10.1016/j.ecl.2007.10.006 endo.theclinics.com

enced surgeons [3]. Because the term macroadenoma refers to any tumor

larger than 1 cm, it is important to keep in mind that the larger thetumor within this category, the more dicult total removal becomes.As an approximate guideline, tumors larger than 2 cm can be completelyremoved only in about 20% of cases [4]. The location of the lesion alsodetermines the outcome. Intrasellar tumors or those with minor infrasel-lar extension can be removed with relative ease. Invasion of the cavern-V may cause diminished corneal reex and ipsilateral pain or paresthesia inthe forehead and the upper cheek.

The inferior surface of the gland is separated by a thin bony wall from thesphenoid sinus. Extension of the tumor into the sphenoid sinus is most oftenasymptomatic. Occasionally, cerebrospinal uid (CSF) rhinorrhea may bea consequence of sphenoidal tumor invasion.

Goals of pituitary surgery

Pituitary lesions may be asymptomatic or may present with mass eects(impaired visual acuity, constricted visual elds, or ophthalmoplegia), withsyndromes of hormone excess, or with hypopituitarism.

The goals of surgery need to be rmly established in each individualpatient. The risks of pituitary surgery performed by an experienced operatorare small but never absent. These risks need to be clearly communicated tothe patient. When surgery is chosen as a treatment option, the following pri-orities must be adhered to:

1. Remove as much tumor as possible to relieve compression of the opticpathways and to eliminate as much hormonally active tissue as possible.

2. Avoid inicting additional neurologic damage.3. Try to protect healthy pituitary tissue.

Several factors play a major role in fullling these objectives.

1. Experience of the surgeon. It has been amply demonstrated that experi-enced pituitary surgeons (those who perform O50 operations per year)have a twofold to threefold higher success rate in hormonally activetumors [1] and a twofold to fourfold lower incidence of surgical compli-cations [2] than less experienced surgeons.

2. Size and location of the tumor. Pituitary lesions smaller than 10 mm indiameter (microadenomas) can be grossly totally removed in 80% to90% of cases. The outcome of surgery for so-called macroadenomas(ie, lesions O10 mm in diameter) is less favorable. Overall, only about50% to 60% of these can be completely removed by the most experi-

52 CHANDLER & BARKANous sinuses generally prevents complete removal. Some suprasellartumors adhere to the optic chiasm, the hypothalamus, or both, andan attempt at complete removal may result in diminished vision orhypothalamic damage.

3. Consistency of the tumor. Most tumors have a soft consistency and canbe curetted easily. In contrast, some tumors are very brous and onlylimited resection is possible. This variable is unpredictable because itcan be discovered only during surgery.

4. Other variables. Abundant vascularity of some pituitary lesions or largevenous sinuses may result in intraoperative bleeding that may force evenhighly experienced surgeons to abandon the attempt.

Interpretation of images

ul inthe

tionative

53TREATMENT OF PITUITARY TUMORSto the brain because it is outside the blood-brain barrier.

Adenomas

Figs. 2 and 3 are examples of large and small pituitary adenomas, respec-tively. Because these tumors arise from within the gland, they tend to causetary. This is normal and represents increased lipid content in this porof the pituitary. The gland should enhance uniformly with contrast relinterpretation of images of common sellar lesions.

Normal pituitary

Fig. 1 shows the coronal and sagittal views of a normal pituitary gland.The size of the gland varies and may ll only the bottom third of the sella ormay be robust and ll the entire sella. The gland is often larger in youngwomen. The stalk should be in the midline on the coronal view and thegland should be symmetric from side to side. On the noncontrast-enhancedT1 views, there is often a hyperintense (bright) spot in the posterior pitui-cation. Some type of angiography (MRI, CT, or conventional) is usefevaluating a vascular lesion such as an aneurysm. The authors outlineWith rare exception, imaging of lesions within the sella and in the para-sellar area is done with MRI. Occasionally, CT is needed to look for calci-Fig. 1. MRI of normal pituitary, T1 with contrast. Coronal view (left). Sagittal view (right).

54 CHANDLER & BARKANthe expected compression and distortion of the gland. A small tumor locatedlaterally will cause a shift of the gland and stalk to the opposite side, oftenassociated with elevation of the diaphragma sellae on the side of the tumor(see Fig. 3). A macroadenoma will usually enlarge the bony sella turcica andmay grow inferiorly, superiorly, or both. Because adenomas typically do notenhance as much as the pituitary itself, it is usually possible to identify the

Fig. 2. MRI of macroadenoma, T1 with contrast. Sagittal view (left): arrow shows pituitary tis-

sue draped over tumor. Coronal view (right): arrow shows optic chiasm elevated by tumor.hyperintense gland draped over the surface of the tumor on T1 images withcontrast (see Fig. 2). It is important to look for the optic chiasm to seewhether it is being elevated by the adenoma. The optic chiasm is alwaysfound just superior to the tumor and will not enhance with contrast. Often,very large tumors invade the cavernous sinus on one side or both sides.

Fig. 3. MRI of microadenoma, T1 with contrast. Coronal view: arrow points to less enhancing

tumor.

Although this invasion rarely results in loss of cranial nerve function, itmakes it impossible to surgically resect the entire tumor.

Sometimes adenomas are cystic, and uid-lled cysts can be identied asbeing dark on T1 images (with or without contrast) and bright on T2images. Hemorrhage within an adenoma (pituitary apoplexy) appears brighton T1 imaging without contrast. This type of hemorrhage almost alwaysoccurs within a sizable macroadenoma. Any material that is bright on T1without contrast is blood or fat.

Meningiomas

The most common location of parasellar meningiomas is the tuberculumsella, which is the midline bony surface along the anterior aspect of the sella.

Craniopharyngiomas

55TREATMENT OF PITUITARY TUMORSCraniopharyngiomas may arise anywhere along the pituitary-hypotha-lamic axis from within the sella itself to within the third ventricle. Themost common location is at the level of the pituitary stalk, just above thesella. On imaging, they are usually a mixture of solid tumor that enhanceswith contrast on T1 and cysts of varying size that are bright on T2(Fig. 5). They may be entirely cystic or virtually entirely solid andThese meningiomas typically compress the optic nerves and cause posteriordisplacement of the pituitary gland. Unlike adenomas, they generallyenhance uniformly with intravenous gadolinium (Fig. 4). This characteristicmakes it dicult to identify the displaced pituitary tissue.

Another common location for meningiomas to arise is the dura of thecavernous sinuses. These tumors are unilateral to the sella and often causecranial nerve dysfunction but not loss of pituitary function or vision.Fig. 4. MRI of meningioma. T1 noncontrast, sagittal view (left): arrow points to normal pitu-

itary; arrowhead denes anterior border of tumor. T1 with contrast, coronal view (right): tumor

enhances brightly and the arrow points to the pituitary.

Lesions that occur primarily within the pituitary stalk and the hypothal-amus include tumors and inammatory lesions. Inammatory lesionsinclude sarcoidosis and Langerhans histiocytosis. Hypothalamic gliomasmay occur in the median eminence of the hypothalamus and upper stalk.Stalk and hypothalamic lesionsenhancing. A plain CT scan is often helpful to show tumor calcication.Such a nding strongly supports the diagnosis of craniopharyngioma,although it may not be present in nearly half of these tumors.

Fig. 5. MRI of craniophayngioma, T1 with contrast. Coronal view (left): arrow points to cystic

component of tumor. Sagittal view (right): arrow points to normal pituitary.56 CHANDLER & BARKANChoristomas (granular cell tumors) are rare tumors that arise from the pitu-itary stalk. Germinomas may arise in the stalk but are often associated witha similar lesion in the pineal region.

Cysts

Primary cysts occur within the sella and are usually referred to asRathkes cysts. They contain material that is often thin like CSF but maybe thick and mucinous. These cysts do not enhance with contrast and areusually darker than an adenoma on T1 images. They are often bright onT2 (Fig. 6), but when the uid is thick and proteinacous, they may not bebright. Abscesses may occur in the pituitary and present as an isointensenonenhancing mass and are often confused with an adenoma.

Dermoid and epidermoid cysts present as complex, often heterogeneouslesions on MRI, usually with some hyperintense fatty material seen on T1imaging.

A so-called empty sella can be dierentiated from an arachnoid cyst, inthat the pituitary stalk can be seen entering the sella and coursing to thecompressed pituitary tissue at the bottom of the sella. In both of these situ-ations, an enlarged sella is seen as lled with CSF (bright on T2).

mas

optic

chiasm. T2 without contrast (right): hyperintense (same as CSF in ventricles).the cavernous sinus, causing ophthalmoplegia. Nasopharyngeal carcinoCarcinomas

It is fortunate that malignant adenomas are extremely rare. It is possible,however, for a malignant tumor to metastasize to the pituitary. Thesetumors cause rapid erosion of the surrounding skull base and often invadeFig. 6. MRI of Rathkes cyst. T1 with contrast (left): hypointense mass with elevation of57TREATMENT OF PITUITARY TUMORSmay appear in the parasellar area but cause erosion from outside the sellaand can usually be distinguished from primary pituitary tumors.

Chordomas

Chordomas arise from the clivus, directly beneath the sella, and shouldnot be confused with intrasellar tumor. They erode the bone of the clivusand provide mixed signal with contrast enhancement on T1 imaging. Theyinvade the skull base and often present with cranial nerve palsies.

Surgical approaches

Although most tumors in the region of the sella are approached by wayof the sphenoid sinus, selected tumors require a dierent trajectory to max-imize tumor removal and minimize the risk of the surgical procedure(Fig. 7). A number of these approaches can be combined.

Transsphenoidal approaches

The sublabial and transnasal transseptal approaches were used in the pastbut involved signicant surgery involving the nasal septum. Theseapproaches could be complicated by septal perforation or by anesthesia of

Direct transnasal transsphenoidal microscope approachGrith and Veerapen [5] in 1987 and Cooke and Jones [6] in 1994

described a transnasal approach involving placing a long narrow speculumtransnasal approach.the incisors. They also required bilateral postoperative nasal packing forseveral days. These approaches have largely been supplanted by the direct

Fig. 7. Diagram of skull base and nasal region demonstrating the approaches to the sellar region.

58 CHANDLER & BARKANdirectly into the nostril all the way back to the sphenoid ostia on one side.By making the mucosal incision at the very back of the nasal airwaypassage, there is no disruption of the midline septum of the nose and, there-fore, less discomfort and no chance of a postoperative septal perforation.After the sphenoid sinus is entered, an excellent view of the anterior wallof the sella is obtained. The sella is opened under microscopic vision andthe dura is opened with a small scalpel. The tumor is removed under directmicroscopic view. Lateral uoroscopy is used to localize the sella in all cases,and frameless stereotactic navigation is used in all microadenomas andrepeat surgeries. This approach generally allows gross total removal of mac-roadenomas and complete removal of microadenomas.

Intraoperative complications are rare but may include injury to thecarotid artery, injury to the optic pathways, injury to the contents of thecavernous sinuses (cranial nerves III, IV, V, and VI), intracranial bleeding,and major CSF leakage. Early postoperative complications are uncommonbut include hematoma formation in the tumor cavity (with compression ofcranial nerves II, III, or IV), CSF rhinorrhea, and epistaxis.

Although the authors perform this approach without the assistance of anears, nose, and throat (ENT) surgeon, many neurosurgeons who do fewertranssphenoidal procedures use the skills of a trained ENT nasal surgeonto assist with the approach to the sella.

pe is

hirdbe removed by way of the lamina terminalis if it has grown into the tTranscranial approaches

Unilateral subfrontal approachThe right-sided unilateral subfrontal approach to the sella is the method

most commonly used for a midline or eccentric right suprasellar lesion(Fig. 8). When the lesion is clearly eccentric to the left, a left subfrontalapproach may be appropriate. The classic subfrontal approach involvesa transcoronal scalp incision to avoid a visible forehead scar and allowsthe elevation of a frontal bone ap.

The frontal lobe is gently elevated and the optic nerve identied. Micro-dissection around the optic nerve is performed, and the tumor is usuallyevident beneath and medial to the optic nerve. Intrasellar lesions may beapproached in the window between the optic nerves and in the windowbetween the optic nerve and the ipsilateral carotid artery. Tumor can alsoExtended transsphenoidal approachThe transsphenoidal approach can be extended into the parasellar areas

for more extensive tumor resection. Jho [7] and Dusick and colleagues [8]used the transnasal route for resection of meningiomas of the planum sphe-noidale region. Mason and colleagues [9] and Dumont and colleagues [10]described a more extensive procedure in which the bone of the planum sphe-noidale is removed and underlying dura and the diaphragma sellae areopened widely to expose the entire infundibulum and the optic chiasm.This procedure is used for cases in which there is a relatively small but hor-monally active portion of the tumor attached to the pituitary stalk.the authors would question whether the view aorded by the endoscoadequate to perform careful dissection within the pituitary gland.Direct transnasal transsphenoidal endoscopic approachThe entire procedure just described using the operating microscope can

be duplicated by using the endoscope. This method has the potential advan-tage of using smaller instruments but has the signicant disadvantage thatonly two-dimensional visualization is possible. The operator looks ata at screen monitor while manipulating instruments in the surgical eld.Although it is true that a 30 to 45 angled endoscope sees further laterallyin the sphenoid sinus, it does not provide three-dimensional imaging of thesella and the pituitary tumor.

The usefulness of an endoscope is in examining the skull base anatomylateral and superior to the sella and occasionally in looking within a tumorbed for residual. With small microadenomas such as in Cushings disease,

59TREATMENT OF PITUITARY TUMORSventricle or if the chiasm is prexed. Care must be taken to avoid injuryto the pituitary stalk and to the undersurface of the optic chiasm. Afterdecompression of the optic pathways and maximum tumor removal, theretractors are removed and the craniotomy closed in the standard fashion.

basilar artery, if needed. This approach is useful for choristomas, wtend to arise more posteriorly and extend back to the brainstem.Pterional approachThe pterional approach involves adding a temporal exposure to the fron-

tal approach described previously. This approach is not usually used forstandard adenomas but can be particularly useful for the resection of com-plex craniopharyngiomas. This approach allows a more lateral exposure ofthe space between the ipsilateral optic nerve and the carotid artery and thespace lateral to the carotid artery. It allows a view all the way back to the

hich

Fig. 8. Diagram showing subfrontal approach to a large sellar region tumor.

60 CHANDLER & BARKANChoice of approach

Well over 90% of sellar and parasellar tumors can be approached trans-sphenoidally. The transcranial approaches described earlier should be usedonly for lesions that extend well into the middle fossa or have a large com-plex suprasellar component. When it is clear that a tumor is based above thepituitary, such as a craniopharyngioma or meningioma, the authors preferthe subfrontal or pterional approach.

How aggressive the surgeon should be is always a matter of judgment,both of the anatomy and the biology of the tumor. Because all macroadeno-mas are invasive of the surrounding dura, it is rarely, if ever, possible toobtain a 100% tumor removal. The goal is maximum safe removaldusuallywell over 95% of the tumor. Attempts to remove intracavernous portions ofthe tumor or strip tumor fragments from the optic nerves are likely to resultin neurologic morbidity.

A few institutions have a magnetic resonance scanner available in theoperating room. Because it is technically impossible for the MRI to clearlydemarcate the residual tumor from the background of operative changes,the intraoperative MRI is limited. This intraoperative imaging technique

p to

sellais small and the anatomy of the sphenoid sinus is complex. It is recommen-

surgery is necessary just to reach a diagnosis. The authors have seen situa-

tions in which metastatic tumors, craniopharyngiomas, meningiomas, andabscesses have mimicked pituitary adenomas.

Pituitary adenomas

Pituitary adenomas are, with rare exception, benign lesions. At the initialencounter, it is important to reassure the patient that the tumor they have isnot cancerous and not a tumor within the brain.

As a rule, pituitary adenomas are slow-growing tumors. Although noexact data are available, the average doubling rate of these rumors is around1 to 2 years. The indications for surgical treatment and the aggressiveness ofsurgery are determined by a number of factors, including the functionalnature of the tumor.

Nonfunctioning adenomas

The main reason to remove a nonfunctioning adenoma is to alleviate orded for routine use by surgeons who perform this operation onlyoccasionally.

Indications for surgery

Ideally, every individual considered for surgery would be evaluated by anendocrinologist and a neurosurgeon trained in pituitary surgery. Althoughthere are always a few patients who fall in the gray areas and can be fol-lowed carefully or undergo tumor resection, most patients provide clearindications to their physicians as to whether they need surgery. Sometimes,needs this guidance less often, but it is a tremendous help when thethe judgment and bias of the surgeon. The authors prefer to rely primarilyon the three-dimensional view of the operating microscope, but others aresatised with the two-dimensional view aorded by the endoscope. The rigidendoscope is a handy adjunct to the microscope during surgery for tumorsthat are lateral in the sphenoid sinus. The authors keep it available duringsurgery but do not use it routinely.

The decision to use frameless stereotactic guidance during surgery alsodepends on the comfort and experience of the surgeon in combinationwith the size and location of the tumor. An experienced pituitary surgeonclear whether this changes short- or long-term results.The decision to use an endoscope during tumor removal is entirely umay result in slightly greater tumor removal in a few patients, but it is not

61TREATMENT OF PITUITARY TUMORSprevent its mass eects, which can be neurologic (eg, compression of theoptic chiasm) or endocrinologic (hypopituitarism). Even when the lattereect is present, it is important to weigh the potential surgical risks in a givenpatient (including even further worsening of hypopituitarism) versus the

bove

cant

debulking of the tumor is usually sucient to decompress the optic chiasm,thus achieving the major objective of surgical intervention.

Incidentally found asymptomatic tumors often pose a treatment di-lemma. The decision to operate depends on the size of the tumor, the func-tion of the pituitary, and the age of the patient.

In all instances, avoidance of surgically induced neurologic complicationsis paramount, even at the expense of incomplete tumor removal.

Functional adenomas

Cushings diseaseVirtually all patients with proven or suspected pituitary-dependent hyper-

cortisolism need to have exploration of their pituitary. It is fortunate thatmost of these patients have microadenomas. Interventions for these micro-adenomas require the highest degree of surgical skills. Because there is noreliable medical therapy for Cushings disease and the mortality and themorbidity of incompletely controlled disease are very high, it is ideal thatthe surgeon removes the entire tumor during the rst operation. Approxi-mately 20% to 30% of patients have tumors that are too small to be de-tected by MRI and that require multiple careful sections of the gland anda keen understanding of which small areas look and feel dierent from nor-mal pituitary tissue.

Residual hypercortisolism justies repeat surgical intervention to the pointof total hypophysectomy. The development of drugs capable of inhibitingtumorous corticotropin secretion may alter the existing treatment paradigm.requires a suprasellar expansion of the tumor in excess of 1 to 1.5 cm athe level of the diaphragma sella.

Although gross total removal of tumor is always a goal, signibenets of restoring the pituitary function because replacement therapy isusually easy.

Headache is believed to be due to the stretching of the diaphragma sellaeby an intrasellar mass. Thus, a small tumor, not distorting the upper con-tour of the pituitary gland, is unlikely to cause headaches.

Invasion of the cavernous sinus by a pituitary adenoma rarely producesophthalmoplegia. Injury to the cranial nerves of the cavernous sinuses ismore likely to happen with sudden pituitary apoplexy or may suggest a me-ningioma or metastasis as an etiology. Unless a schwannoma of cranialnerve V is suspected, no attempt should be made to remove tissue fromwithin the cavernous sinus because it will likely lead to permanentophthalmoplegia.

Thus, the strongest indication for surgical decompression of a nonfunc-tioning pituitary adenoma is threatened vision. This situation usually62 CHANDLER & BARKANAcromegalyMost acromegalic patients have macroadenomas. Although surgery only

results in complete endocrine remission in less than 50% of patients, it

esia.-line

treatment to virtually all patients who have newly diagnosed acromegaly.

ausethese tumors should not, as a general rule, be treated surgically. Instead, med-

dal-ity. In general, when the tumor is surgically accessible, it should be removed

or at least debulked. Most of these tumors are macroadenomas and needpostoperative medical therapy.

Pituitary apoplexy

Pituitary apoplexy refers to acute infarction (and often associated hemor-rhage) of a pituitary adenoma. As a rule, tumors undergoing apoplexy aresubstantial macroadenomas, and the acute expansion of tumor size is fre-quently accompanied by severe headache, vomiting, altered consciousness,visual-eld defects to the point of blindness, and ophthalmoplegia. Mostof care of these lesions. Thyrotropinomas are sensitive to somatostatinalogs, and this medication can be used as a primary or postoperative moical therapy with dopamine agonists should be oered. The authors prefer torecommend initial treatment with dopamine agonists, even in patients whohave microadenomas, because the recurrence rate is high after surgery.

Surgery, however, may be indicated in patients who are unresponsive toor intolerant of dopamine agonists. Some prolactinomas may contain largecystic or hemorrhagic areas that are unlikely to respond to medications witha degree of shrinkage that is sucient to decompress the optic chiasm.

ThyrotropinomasHyperthyroidism due to a thyroid-stimulating hormone secreting ade-

noma is a rare disease. Thus, there are no universal agreed-on standardsan-thyroidism, chest wall lesions, and so forth).It is important to establish a correct diagnosis of trueprolactinomasbecA surgeon should strive for an as complete resection of the tumor as possi-ble, without risking neurologic damage.

ProlactinomaCareful history and clinical examination are mandatory to exclude non-

tumorous causes of hyperprolactinemia (medications, severe primary hypo-a patient refuses surgery or is in poor general health, precluding anesthThe authors believe that surgery must be recommended as a rstprovides a very signicant fall in growth hormone and insulin-like growthfactor-I levels in all patients. Even a partial fall in hormone levels improvessubsequent response to other treatments [11]. Primary medical therapy withsomatostatin analogs can normalize growth hormone hypersecretion and ef-fect tumor shrinkage [12,13] and can be used in selected cases such as when

63TREATMENT OF PITUITARY TUMORSof these patients have severe hypopituitarism on admission. In some pa-tients, initial CT or MRI reveals massive intratumoral hemorrhage (brighton noncontrast studies), whereas in other patients, the tumor appears ische-mic (iso- or hypointense on noncontrast studies).

uire

Meningioma

Meningiomas are benign tumors and can be followed with serial imaging

if they are not large and are not causing symptoms. It is unfortunate thatmany tumors in the parasellar area cause signicant compression of theoptic pathways and require surgery to decompress these structures. Mostmeningiomas are approached intracranially, again usually by the subfrontalor pterional approach. Most of these tumors can be removed in a gross totalfashion because they are dural based and do not protrude into the third ven-tricle. The goal of surgery is to reach a diagnosis and safely decompress thevisual pathways. Some of these tumors invade the optic foramina and com-press the optic nerves in this area. It is often necessary to carefully drill awaythe overlying bone of the canal to remove the entire tumor.surgery and are operated on with an intracranial approach to their tumor.Often, these tumors are very adherent to the undersurface of the optic chi-asm or the third ventricle, and attempt at complete removal may result inadditional loss of vision or a signicant neurologic decit.

Some craniopharyngiomas may be approached surgically by way of thetranssphenoidal approach, especially when they are largely cystic andhave extended down into the sella. It is also possible to use the extendedtranssphenoidal approach described earlier to remove tumors that are par-tially solid and even extend up into the region of the third ventricle. Thesame guidelines apply to being cautious about adherence to the chiasmand third ventricular wall.

Most patients need a course of radiation after incomplete removal ofa craniopharyngioma. In children, it is wise to postpone radiation as longas possible, even if repeated surgery is needed.When a craniopharyngioma is suggested by MRI, most patients reqThe appropriate management requires urgent administration of steroidsin stress doses, uid administration, and pain control. The role of urgentsurgery is controversial: some studies found better neurologic recovery afterpituitary decompression done within hours to days after the onset of clinicalsymptoms [1416], whereas other studies did not [17,18]. Taking intoaccount potential dire consequences of apoplexy (permanent visual compro-mise) and the low risk of transsphenoidal decompression, it is prudent toevacuate the accessible part of the tumor to relieve the intrasellar pressureas soon as medically possible in patients who have obvious (especially rap-idly progressing) cranial nerve decits.

Craniopharyngioma

64 CHANDLER & BARKANMeningiomas that arise from within the dura of the cavernous sinusregion are usually radiated without a biopsy. Modern MRI can providean extremely accurate diagnosis, and radiation is eective in controllingtumor growth in most cases.

are often found incidentally and rarely progress. Close follow-up with

gerysuggests a metastatic malignant tumor, surgery is usually terminated and

ikely

esec-may be indicated. Cushings disease patients who have had successful rModest recurrence of a nonfunctional macroadneoma in the years fol-lowing initial surgery favors radiation therapy [19]. Large recurrence, espe-cially with visual impairment, requires repeat tumor debulking beforeradiation therapy.

Patients who have failed surgery for Cushings disease or have recurrenceof the disease are often candidates for repeat surgery. If hyperplasia is diag-nosed and the patient is not in remission, then complete hypophysectomytency, or excessive vascularity, then further aggressive surgery is unlto be successful and may result in signicant morbidity.adjunctive treatments are considered.

Reoperation

A decision to reoperate on a pituitary tumor requires careful integrationof all the available information. If an experienced surgeon did not accom-plish complete tumor removal because of its invasiveness, brotic consis-biopsy, usually transsphenoidally. When a frozen section during surMRI is mandatory.

Metastasis

Metastases are rare and often not suspected until surgery has been per-formed. Any unknown progressive or symptomatic lesion must undergoCysts

Anumber of patients have purely cystic lesionswithin the sella.When theselesions are small and the pituitary function is normal, they should be followedwithMRI. If they enlarge or cause symptoms, then transsphenoidal surgery isusually eective in draining the cyst uid and in reaching a diagnosis. It isimportant to keep in mind that when a craniopharyngioma or abscess is sus-pected, surgery is indicated irrespective of the size of the lesion.

Stalk and hypothalmic lesions

These lesions can be approached only through an intracranial approach,with panhypopituitarism being an almost inevitable consequence. Thus, thedecision to operate on such lesions should never be reached lightly. Only tu-mors that are strongly suspected to be malignant or are severely aectingvision should be considered for surgical intervention. Small stalk lesions

65TREATMENT OF PITUITARY TUMORStion of a microadenoma and experience a recurrence often benet fromreoperation.

The authors rarely reoperate for treatment of continued biochemicalevidence of acromegaly and rely on medical treatment or radiation therapy.

109(1):6370.

[17] Gruber A, Clayton J, Kumar S, et al. Pituitary apoplexy: retrospective review of 30patientsdis surgical intervention always necessary? Br J Neurosurg 2006;20(6):37985.

[18] Sibal L, Ball SG,ConnollyV, et al. Pituitary apoplexy: a review of clinical presentation,man-

agement and outcome in 45 cases. Pituitary 2004;7(3):15763.Likewise, most patients who have persistent prolactinomas may benetfrom adjustment of medical therapy or occasionally from radiation.

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Treatment of Pituitary Tumors: a Surgical PerspectiveClinical neuroanatomy of the pituitaryGoals of pituitary surgeryInterpretation of imagesNormal pituitaryAdenomasMeningiomasCraniopharyngiomasStalk and hypothalamic lesionsCystsCarcinomasChordomas

Surgical approachesTranssphenoidal approachesDirect transnasal transsphenoidal microscope approachDirect transnasal transsphenoidal endoscopic approachExtended transsphenoidal approach

Transcranial approachesUnilateral subfrontal approachPterional approach

Choice of approachIndications for surgeryPituitary adenomasNonfunctioning adenomasFunctional adenomasCushings diseaseAcromegalyProlactinomaThyrotropinomas

Pituitary apoplexyCraniopharyngiomaMeningiomaCystsStalk and hypothalmic lesionsMetastasis

ReoperationReferences