Multiregional sampling reveals a homogenous distribution of Ki-67 proliferation rate in pituitary adenomas

Summary. Ki-67 antigen is used as a marker of proliferative activity that is linked to growth rate, invasiveness and prognosis of pituitary adenomas. So far the distribution of Ki-67 index within an individual adenoma has not been investigated. If Ki-67 antigen expression differs significantly within an individual pituitary adenoma, a sampling error may result when assessing small fragments of adenoma tissue. Such a potential error would diminish the value of Ki-67 as a tool for postoperative patient management considerations. The aim of the present study was to assess Ki-67 proliferation rates in different regions of pituitary adenomas and to statistically analyse these data for potential regional differences within each tumor.Ki-67 proliferation index was assessed in smear preparations of 100 specimens of 26 consecutive patients operated on for pituitary adenoma in the Department of Neurosurgery, Medical University Vienna. Depending on the size and extent of the tumor, a mean of 4 tissue samples (range 2–8) was selected intraoperatively from each adenoma from endosellar, suprasellar, parasellar, and basal sellar dural locations.Overall mean cell proliferation rate measured by Ki-67 was 1.81±0.90% (range 0.33–3.43%). Histologically invasive adenomas had significantly higher mean Ki-67 proliferation index in all samples from the same tumor than non-invasive adenomas (2.01±0.91% vs. 1.11±0.59%; P=0.024). Multiregional sampling revealed a homogenous distribution of Ki-67 index throughout an individual adenoma with no significant differences between any two different regions on t-test.Our data confirm that location of a biopsy does not influence Ki-67 index. Therefore, Ki-67 index of a single biopsy is representative for the whole individual adenoma. Thus Ki-67 index can be considered a reliable parameter for assessment of cell proliferation rate in adenoma biopsies and may be used for postoperative patient management considerations.     

The correlation of Ki-67 staining indices with tumour doubling times in regrowing non-functioning pituitary adenomas

Summary In order to improve our ability to predict the regrowth of nonfunctioning pituitary adenomas, we tried to assess the correlation between growth fractions with Ki-67 and PCNA (proliferating cell nuclear antigen) and tumour doubling times in regrowing tumours, and also to find out any difference of growth fractions between the regrowing and the cured cases.In 33 patients with non-functioning pituitary adenomas, 14 cases including 11 with cavernous sinus invasion showed residual tumour on MRI after the operation (regrowing group) and 19 cases had no tumour regrowth on MRI within 5 years after the operation (cured group). Immunocytochemical studies were done with monoclonal antibodies (anti-PCNA, anti-Ki-67: MIB-1). The growth fraction of each tumour was estimated by calculating the ratio of the positive nuclei to the total number of tumour cells with the aid of an image analyser (Mac SCOPE). The tumour doubling times were estimated from serial CT or MRI with the aid of the image analyser (NIH image).Ki-67 staining indices ranged from 0.2% to 1.5% (n = 14, 0.86±0.10%; mean±SEM) in the regrowing group, and from 0.1% to 0.5% (n = 19, 0.23±0.03%) in the cured group. PCNA staining indices of the regrowing group ranged from 0.6% to 24% (n = 14, 3.7±1.6%). In the regrowing group, the tumour doubling times ranged from 200 to 2550 days (930±180 days), and showed a significant inverse correlation with Ki-67 staining indices, but no correlation with PCNA staining indices. The regrowing group showed a significantly higher Ki-67 staining index (n = 14, 0.86±0.10%) than the cured group (n = 19, 0.23±0.03%) (p<0.01).These results indicate that immunocytochemical studies using MIB-1 may be better than those with PCNA for the prediction of regrowth in non-functioning pituitary adenomas. Immunocytochemical study with MIB-1 could lead to the accurate prediction of the rapid regrowing lesions in non-functioning adenomas.     

单鼻孔-经蝶窦入路切除垂体腺瘤70例报告

目的探讨显微神经外科技术经单鼻孔-鼻中隔根部-经蝶窦入路切除垂体腺瘤手术入路的临床效果. 方法显微镜下长鼻镜辅助观察、扩张中鼻道,扩张器置入直达蝶窦前壁、骨性鼻中隔根部,将鼻中隔自根部折断连同对侧鼻黏膜一起推向对侧,余步骤同传统经蝶手术. 结果全组70例中,62例近全切除(>95%),6例大部切除(76%～95%),2例仅为部分切除(≤75%).无手术死亡.术后24例一过性尿崩,均于3周内自愈;8例脑脊液鼻漏,5例卧床2周自愈,3例行腰大池引流治愈.48例随访3个月～2年,平均7个月,2例复发. 结论单鼻孔-鼻中隔根部-经蝶窦入路切除垂体腺瘤疗效满意,对手术通道即鼻部组织损伤小,不必分离鼻中隔及两侧黏膜,手术技术容易掌握,省时间,并发症少.     

Complications of transsphenoidal surgery in patients with pituitary adenoma: experience at a single centre

Summary Objective. This paper reports the complications of transsphenoidal surgery for pituitary adenomas in a series of 1240 consecutive patients operated at our Institute between 1990 and 2004 (first operations) and indicate the clinical characteristics of patients which affected surgical morbidity and mortality. Methods. According to tumour type, there were 420 (33.9%) non-functioning pituitary adenomas (NFPA), 349 (28.1%) GH-secreting, 288 (23.2%) ACTH-secreting, 155 (12.5%) prolactin (PRL)-secreting, and 28 (2.3%) TSH-secreting adenomas. The mean age of patients was 43.7 ± 0.4 yr and 122 patients (9.9%) were 65 yr or older; the female/male ratio was 1.5/1. There were 370 (29.8%) microadenomas and 870 (70.2%) macroadenomas of which 54 (4.4%) were giant adenomas. Results. The series mortality was 0.2%, the medical morbidity 1.9%, and the surgical morbidity 3.5%. Medical complications were significantly more frequent in patients older than 65 yr (4.9 vs. 1.4%; p = 0.009) and in patients with giant adenomas (5.6 vs. 1.6%; p = 0.03). Multivariate analysis showed that both variables were independently associated with a higher morbidity rate. The surgical morbidity was increased in giant adenomas (15 vs. 3%; p = 0.0001), in NFPA (6.2 vs. 2.1% in secreting adenomas; p = 0.0002) and in patients older than 65 yr (6.6 vs. 3.1%; p = 0.05). Multivariate analysis showed that only giant size was independently associated with an increased surgical morbidity rate. Conclusions. In our experience, the size of the adenoma was a risk factor for medical and surgery related complications and age over 65 yr for medical complications alone.     

Surgery on pituitary adenomas in patients in a subarctic region

Summary The present series consists of 18 consecutive patients with pituitary adenomas operated on between 1977 and 1979 using the transfrontal route. Ten adenomas were 10, 20 or 30 times the normal maximum size of the pituitary measured according to Di Chiro and Nelson's (2) index (Table 2). Tumours without obvious suprasellar growth were operated on using the trans—sphenoidal route and thus are not included in the present series.Large and giant pituitary adenomas are preferably removed by the transfrontal route and using microsurgical techniques. Really poor vision associated with very large tumours seem to improve but not to normal level. A blind eye stays blind. Less poor vision returns to normal (Table 4). Prolactin values associated with giant prolactinomas are extremely high and may remain raised even after apparently radical extirpation. Isolated tumour-containing sellar crypts associated with these large tumours may be responsible for this observation. Postoperative radiotherapy and bromocriptine administration therefore seem advisable. Further operations may be necessary on patients with extensive posterior or lateral growths. Redundant partially intraosseal tumour fragments may be more easily removed later, possibly owing to the beneficial effects of radiation therapy. It is hoped that large and giant adenomas in the future will pass into history, even in the peripheral parts of the world. The trans—sphenoidal approach is always a better solution than the transfrontal approach whenever it can be carried out, but it requires earlier diagnosis.Presented at the 32. Scandinavian Neurosurgical Society Meeting in Linköping, September 3–6, 1980.     

Clinical and cytofunctional classification of pituitary adenomas: Proposal of a new classification

Summary Recent methodological advances in immunohistochemistry, ultrastructural techniques, hormonal assays, resolution imaging and molecular biology techniques have provided new insights into the pathology, function and cytogenesis of pituitary adenomas. Pituitary adenomas have been classified historically on the basis of tinctorial affinities, followed by the basis of ultrastructure and immunohistochemistry. The current development of technologies necessitate the new classification of pituitary adenomas which integrates these numerous parameters as well as the clinical manifestations. For this purpose, we suggest a new clinico-cytofunctional classification of pituitary adenomas, which is based on these clinical manifestations and integrates the information on biology, imaging function and ultrastructure. This classification which corresponds to current advances will not only provide pertinent clinical data but facilitate better understanding of the biology and nature of these complexed lesions.     

Developments in surgical treatment of pituitary adenomas

Summary Progress in pituitary surgery has arisen with the introduction of microsurgical technique, endocrinological functional tests and computerized tomography of the skull.Using such microsurgical procedures, the transsphenoidal approach to the sella with selective adenomectomy is rendered possible. Furthermore, this operative approach is recommended also for pituitary tumours growing symmetrically to the suprasellar region.Endocrinological functional tests permit exact measurement of pituitary insufficiency and hormonal excesses, including all hormones of the anterior pituitary; today, only 30% of the adenomas are regarded as hormonally inactive. The indication to operate, the approach and the extent of the operative procedures depend on these results. Further, the operative result can be controlled by endocrine tests; in this way treatment of acromegaly can be improved: in patients with intrasellar adenomas GH-excess can be normalized in 90% of the patients.Selective adenomectomy has also improved the treatment of Cushing's disease. In women with hyperprolactinemic amenorrhea, who wished to have children, ovarian cycles and pregnancy occurred. In the case of prolactinomas, for the first time medical treatment of pituitary adenomas has been successful. Computerized tomography of the skull is the most important examination in order to localize a tumour and to determine its extent whereby the operative procedure (transsphenoidal, transcranial) is decided. After operation, the radicality of the operation can thus be documented and in the case of tumour residuals a second operation may then be indicated.

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Zusammenfassung Die Fortschritte in der Hypophysenchirurgie basieren auf der mikrochirurgischen Technik, der endokrinologischen Funktionsdiagnostik sowie der Computer-Tomographie.Das mikrochirurgische Vorgehen hat den transsphenoidalen Zugang mit selektiver Adenomektomie ermöglicht. Darüber hinaus empfiehlt sich dieser Operationsweg auch bei symmetrisch suprasellär aus der Sella herausgewachsenen Geschwülsten.Endokrinologisch lassen sich mit Hilfe der Funktionsdiagnostik Hypophysen-Insuffizienzen und Hormon-Exzesse, die alle Vorderlappenhormone betreffen können, exakt bestimmen; als inaktiv gelten heute nur noch etwa 30% der Adenome. Von diesen Ergebnissen hängt die Indikation zur Operation, die Art und das Ausmaß des operativen Eingriffs ab. Darüber hinaus läßt sich der Operationserfolg endokrinologisch kontrollieren; auf diese Weise ist z. B. in der Behandlung der Akromegalie eine Normalisierung des GH-Exzesses bei 90% der intrasellären Adenome erreicht worden.Die selektive Adenomektomie hat auch die Behandlung des hypothalamisch/hypophysären Cushing-Syndroms bereichert und bei Frauen mit hyperprolaktinämischer Amenorrhoe und Kinderwunsch die Wiedererlangung ovarieller Zyklen und Schwangerschaften ermöglicht. Für die Prolaktinome zeichnet sich erstmals eine erfolgversprechende medikamentöse Therapie der Hypophysenadenome ab.Zur Lokalisation und Bestimmung der Ausdehnung der Geschwülste ist die Computer-Tomographie die entscheidende Untersuchung, welche die Wahl des operativen Zugangs (transsphenoidal, transkranial) bestimmt und postoperativ die Radikalität des Eingriffs belegt und im Falle verbliebener Tumorreste zu einer zweiten Operation, u. U. auf dem anderen Operationsweg, Anlaß geben kann.

     

Proliferation, Vascular Endothelial Growth Factor Expression and Cavernous Sinus Invasion in Growth Hormone Secreting Pituitary Adenomas

Summary  Surgical cure of growth hormone producing pituitary adenomas (GHomas) becomes difficult when they invade the cavernous sinus (CS). Tumour proliferative activity and angiogenesis are thought to be required for tumour growth and invasion, and vascular endothelial growth factor (VEGF) activates neovascularization around tumours. In this study, the mechanism and clinical significance of CS invasion is analysed. In 25 surgically treated GHomas, the extent of CS invasion was classified as high (Knosp's grade 3 and 4), and low (grade 0, 1 and 2) MR grades, and the MR grades were compared with tumour proliferative potential (Ki-67 expression), angiogenetic demand (VEGF expression), volume of adenomas and serum hormone levels.  The Ki-67 index of high MR grade adenomas (1.17±0.62%) was significantly higher than that of low MR grade adenomas (0.55±0.42%, p=0.027), whereas VEGF expression showed no significant correlation with MR grades (p>0.999). Tumour volume also showed a significant correlation with MR grade (p=0.002). VEGF expression was not correlated with serum hormone level and volume, but was correlated with tumour proliferative potential. Proliferative potential and tumour volume were two independent factors related to CS invasion. Although VEGF expression was not a direct factor related to CS invasion, it may indirectly play a role in activation of tumour aggressiveness, which is required in CS invasion.  Our results show that high MR grade adenomas have higher proliferative ability. In order to improve the surgical outcome, pre-operative medical debulking is indicated, particularly, in such adenomas.     

Expression of cyclin kinase inhibitor p21/WAF1 protein in pituitary adenomas: correlations with endocrine activity,but not cell proliferation

Summary.  p21/WAF1 blocks cell cycle progression through inhibition of cyclin/cyclin-dependent kinases (cdks) complexes and, simultaneously, has been associated with cell cycle exit and the process of differentiation. In this series, the expression of p21/WAF1 was assessed immunohistochemically in 47 cases of pituitary adenomas in relation to endocrine activity and cell proliferation. To evaluate cell proliferation, a monoclonal antibody, MIB-1, against Ki-67 antigen was used in all of the available cases. The study revealed positive p21/WAF1 staining in 24 cases of 26 functioning parenchymas, whereas 14 cases of 21 non-functioning parenchymas stained negative. The MIB-1 index ranged from less than 1% to 5.1% (mean: less than 1.7%) in functioning adenomas, and from less than 1% to 3.6% (mean: less than 1.6%) in non-functioning adenomas. Regardless of endocrine activity, p21/WAF1 positivity did not correlate with the MIB-1 index. Double staining techniques revealed the co-expression of p21/WAF1/GH or p21/WAF1/PRL in functioning adenomas. In 22 cases of p21/WAF1-positive functioning adenomas, p21/WAF1 immunoreactivity was seen in the cytoplasma as well as nuclei. These results indicate that in pituitary adenomas, p21/WAF1 expression is associated with endocrine activity, but not with cell proliferation. Taken together with recent findings demonstrating that cytoplasmic p21/WAF1 acts as an inhibitor of apoptosis, it is possible that pituitary adenomas expressing cytoplasmic p21/WAF1 have resistance against DNA-damaging agents such as ionizing radiation.     

Vanishing pituitary mass revealed by timely magnetic resonance imaging: two cases of spontaneous resolution of nonfunctioning pituitary adenoma

Summary Spontaneous necrosis of a pituitary adenoma is not rare but represents a very unlikely way of curing a nonfunctioning pituitary adenoma. We report two cases of nonfunctioning pituitary adenoma, one of them with a family history of pituitary adenoma, in whom spontaneous complete resolution occurred through the necrosis of previously well-delineated adenoma. Sequential magnetic resonance imaging (MRI) scans provided clear evidence of the event, resulting in an empty sella. In the present cases, the pituitary necrosis was entirely asymptomatic with the exception of an initial atypical headache in one case, and cured the patients as well as a surgical procedure would have done. This exceptional curative process, however, should certainly not be relied on and does not rule out the possibility of recurrence.     

Tumour ploidy in DNA histograms of pituitary adenomas

Summary DNA analysis was performed by flow cytometry (FCM) in 59 cases of different types of pituitary adenomas who underwent microsurgery and were actively followed over a period of 3–6 years. Aneuploid DNA patterns were detected in 12 (20%) cases. Frequency of aneuploidy was highest in prolactin-secreting (36%) as compared to 17% in GH- and 7% in non-secreting adenomas. Some adenoma parameters valid for tumour growth, such as rate of recurrences and mitotic index, were correlated with aneuploidy of the tumour. FCM studies are, therefore, recommended to gain further parameters for the estimation of proliferative activity of pituitary adenomas.     

Apoplexy accompanying pituitary adenoma as a complication of preoperative anterior pituitary function tests

Summary Pituitary apoplexy occurs as a very rare complication of the pituitary function test. We have experienced two cases of pituitary apoplexy following anterior pituitary function tests for preoperative assessment: a triple bolus test and a TRH test. To elucidate such a rare complication, we outline our two cases and review 28 cases from the literature. The clinical characteristics, etiology, pathophysiology, and diagnostic and therapeutic implications are also discussed. The combined data suggest that pituitary function tests have the potential to precipitate pituitary apoplexy, and its manifestations range from a clinically benign event to a catastrophic presentation with permanent neurological deficits or even death, although most patients may fortunately have a good outcome. We suggest that the pituitary function test should not be done as a routine test, and when such a test is planned, the patient should be observed with caution for any symptomatic changes for at least 2 hours following the test for appropriate treatment. Further, MRI, especially enhanced studies, may provide an earlier diagnosis of the pituitary apoplexy since CT scan images often fail to demonstrate either density changes or obvious enlargement of the pituitary adenoma at the acute stage.     

Endoscopic treatment of pituitary abscess: two case reports and literature review

Pituitary abscess is a rare entity and the correct diagnosis is still difficult before surgery. More than 210 cases have been reported in the medical literature, mostly in the form of isolated case reports. We report two cases of pituitary abscess treated endoscopically and we review the literature. A 30-year-old woman and a 35-year-old man were admitted with a history of pituitary dysfunction. Patient 1 presented with polyuria, polydipsia, amenorrhea, headache, and visual impairment. Magnetic resonance imaging showed a cystic intra- and supra-sellar lesion with ring enhancement after contrast injection. Patient 2 presented with frontal headache, proptosis, painful ophthalmoplegia, visual impairment, and fever. Eight years before the patient had undergone a transphenoidal surgery for Prolactinoma. Magnetic resonance imaging revealed a sellar lesion extending into the cavernous sinus and carotid artery bilaterally. Both patients underwent endoscopic transnasal-transsphenoidal exploration. Intraoperative diagnosis of pituitary abscess was made. The postoperative courses were uneventful. Antibiotic therapy was performed in both cases. Only three cases of endoscopic treatment of pituitary abscess have been reported in the literature. We recommend early management by endoscopic transphenoidal surgery for pituitary abscess: this technique is safe, with minimal blood loss, short operating time, low morbidity, and brief hospital stay.     

Presurgical octreotide treatment in acromegaly: no improvement of final growth hormone (GH) concentration and pituitary function. A long-term case-control study

Summary Background. The effect of presurgical long-acting somatostatin analogue (SSA) treatment on operative outcome in acromegaly is as yet uncertain and long-term observations are lacking. We evaluated in an acromegaly case-control study the effect of octreotide pre-treatment on short- and long-term postoperative GH concentrations, pituitary function and glucose tolerance.Methods. 48 patients with a pituitary macro-adenoma – micro- and giant adenomas excluded – were evaluated. 24 patients received presurgical octreotide treatment (secondary surgery, prospectively studied). Another 24 thoroughly matched patients had been operated on without prior octreotide therapy (primary surgery, retrospective evaluation). No patient had received any other treatment prior to operation/octreotide. Standardized testing was performed at diagnosis, following octreotide treatment, after surgery and then yearly for 10.3±0.9yrs (mean±SE, primary surgery) and 4.1±0.6yrs (secondary surgery). Immediate and 4-year postoperative results were compared. All work-up was strictly identical in both groups, except for imaging techniques. Partial remission was defined as mean GH profile (6-h/7-point) concentration <2.5µg/L, and complete remission as GH nadir <1µg/L during OGTT plus normal IGF-I concentration (when available).Findings. The median profile GH (µg/L) values and the OGTT GH nadir values post-surgery (2.4/1.0 vs 1.8/0.7, primary and secondary surgery, resp.) as well as 4yrs later (2.1/1.15 vs 2.3/0.8) were not significantly different between the groups. The 10-year results of the primary surgery group were not significantly different from its 4-year results. Subgroup analysis of pre-treated patients revealed no significant difference between those with and without tumour shrinkage, or between those with and without parasellar tumour extension. Postoperatively pituitary function was not significantly different between the groups. After 4-years the pituitary-adrenal axis was slightly more impaired in the secondary surgery group rather than following primary surgery, while the pituitary-gonadal axis was not different.Conclusion. Presurgical octreotide treatment has no significant short- or long-term beneficial effect on GH concentration or pituitary function.     

Vascular studies in the preoperative evaluation of pituitary adenomas before transsphenoidal surgery

The transsphenoidal approach is being increasingly utilized in the surgical treatment of pituitary microadenoma. Even with high-resolution and dynamic computed tomography (CT) scanning, subtle vascular anatomic variants and other vascular anomalies involving the parasellar carotid arteries cannot always be clearly defined. Five cases are described in which evaluation by digital intravenous subtraction angiography or standard carotid arteriography provided useful preoperative information before transsphenoidal surgery. The implications of these findings are discussed.     

The effectiveness of administering a minimal dose of octreotide long-term prior to surgery for insulinoma: Report of a case

(Received for publication on May 31, 1999; accepted on Jan. 7, 2000)     

Transsphenoidal approaches to the pituitary: a progression in experience in a single centre

Background  Evolving of a single centre by means of different transsphenoidal approaches during the survey of methodological advances in pituitary surgery is presented. Materials and methods  Ninety-three consecutive patients with pituitary adenomas underwent transphenoidal pituitary operations at Gulhane Military Medical Academy from January 1996 to October 2007. Retrospective chart-based analysis of the surgical methods of transsphenoidal pituitary adenoma operations were done. Surgical methods were described. Outcomes and complications were presented. Attention is focused on the methodology of different surgical techniques of pituitary surgery. Findings  During the evaluation period, 12 Sublabial approaches (1996–1998), 13 transseptal transsphenoidal approaches (1999–2000), 15 endonasal transsphenoidal approaches (2000–2004), 25 endoscopy assisted endonasal approaches (2002–2006) and 28 pure endoscopic endonasal approaches (2006–2007) were performed. Conclusions  Technologic advancements in endoscopy and gaining experience in pituitary surgery drives neurosurgeons toward less invasive approaches.     

Sonographically documented stable seminoma: a case report

Seminoma of the testis has a diverse natural history. We report a unique case of histologically confirmed classic seminoma in a 32-year-old patient documented by ultrasound on two occasions one year apart. The tumor size did not change during that time. We explore the possibility of a dichotomy in growth within seminoma and the need to identify molecular methods to predict the subset of tumors that behave biologically less aggressive.     

Surgical removal of growth hormone-secreting pituitary adenomas with intensive microsurgical pseudocapsule resection results in complete remission of acromegaly

Although some investigators recommended surgical removal of the borders between pituitary adenoma and the surrounding normal pituitary gland, there is so far little documentation of how intensive dissection of the border zone affects the actual clinical remission rate of pituitary adenomas. We investigated the precise histological characteristics of the boundary, using surgical specimens from patients who underwent intensive resection of microsurgical pseudocapsule of growth hormone (GH)-secreting pituitary adenomas. Furthermore, we compared the remission rate of acromegaly between subjects with (Group 1) and without (Group 2) intensive resection of microsurgical pseudocapsule in order to correlate the histological complete resection and endocrinological remission. Histologically, most adenomas were in direct contact with normal pituitary gland that formed an increased fibrous component facing the adenoma, without a true histological pseudocapsule. It was impossible to dissect the tumor at exactly the tumor–normal pituitary interface for the whole extent of the pituitary adenoma during surgery, and complete removal of the tumor inevitably included a portion of normal tissue (microsurgical pseudocapsule). The biochemical remission rate was significantly higher in Group 1 than in Group 2 (90.0 vs 61.1%), and Group 1 showed no additional postoperative pituitary hypofunction. The present results suggested that intensive resection of the microsurgical pseudocapsule is essential to accomplish histological and endocrinological total resection of the GH-secreting pituitary adenomas for remission of acromegaly.     

Objective criteria for successful transsphenoidal removal of suprasellar nonfunctioning pituitary adenomas. A prospective study

Summary Background. Despite ample experience with transsphenoidal surgery, objective data on which suprasellar tumour expansion and growth pattern allows for radical adenoma resection are still sparse. Hence, we have performed a prospective study to establish the predictive value of tumour dimension and shape for the intra-operative descent of the diaphragma, the completeness of tumour resection and the outcome of patients harbouring pituitary adenomas with suprasellar extension. Method. Included in the study were 105 patients with nonfunctioning pituitary adenomas and suprasellar extension who underwent primary transsphenoidal surgery between January 1998 and December 2005. The precise suprasellar extension, the degree of dumbbell-shape, the configuration of the adenomas and the depth of the pituitary fossa were evaluated. Completeness of resection was assessed by MRI at 3 months postoperatively. Findings. The mean cranio-caudal diameter of the tumours was 28.0 mm (range 9.2–57.8 mm). On average, the suprasellar extension measured 11.9 mm (range 2.1–25.8 mm). Total removal of the suprasellar tumour was accomplished in 83% (87 of 105) of the patients. A second operation for residual adenoma was only indicated in 2 cases. The vertical intracranial extension was the strongest independent predictor of subtotal resection (p < 0.001). Irregular and multilobular configuration was a second highly-significant and independent predictor for incomplete resection (p < 0.003). In contrast, dumbbell-shape and shallow pituitary fossa were not independent predictive factors for incomplete tumour resection. The complication rate was very low. None of our patients suffered postoperative rhinorrhea, meningitis or visual deterioration. Conclusions. One-stage transsphenoidal surgery allows total or near-total resection of most suprasellar pituitary adenomas with low surgical morbidity. Quantitative assessment of tumour dimension and configuration contributes to establishing guidelines for the selection of the appropriate approach and prediction of surgical outcome.