Attitudes of young neurosurgeons and neurosurgical residents towards euthanasia and physician-assisted suicide.

BACKGROUND: Euthanasia and physician assisted suicide (PAS) are two controversial topics in neurosurgical practice. Personal attitudes and opinions on these important issues may vary between professionals, and may also depend on their location since current legislation differs between European countries. As these issues may have significant impact on clinical practice, the goal of the present study was to survey the opinions of neurosurgical residents and young neurosurgeons across Europe with respect to euthanasia and physician assisted suicide. DESIGN: We performed a survey among the participants of the European Association of Neurosurgical Societies (EANS) training courses (2011-2012), asking residents and young neurosurgeons nine questions on euthanasia and PAS. For the analysis of this survey, we divided all 295 participants into four European regions (North, South, East, West). RESULTS: We found that even though most residents are aware of regulations about euthanasia or PAS in their country or hospital, a substantial number were not aware of the regulations. We observed no significant differences in terms of their opinions on euthanasia and PAS among the four European regions. While most are actually in favor of euthanasia or PAS, if legally allowed, under appropriate circumstances, very few neurosurgeons would be willing to actively participate in these end-of-life practices. CONCLUSIONS: The results of this first survey on neurosurgical residents' attitudes towards euthanasia and PAS show that a significant number of residents is not familiar with national and/or local regulations regarding euthanasia and PAS. If legally allowed, most residents would be in favor of euthanasia and PAS, but only a minority would be willing to actively participate in these practices. We did not observe a difference in stances on euthanasia and PAS among residents from different regions in Europe.

An unusual tumour causing neonatal respiratory distress.

PROBLEM: We present the case of a term neonate referred shortly after birth because of breathing and feeding difficulties. METHODOLOGY: Fiber-endoscopic examination of the nasal cavity showed a pendulating mass in the nasopharynx. RESULTS: A complete surgical resection was performed and the baby recovered completely. Microscopic examination of the mass showed an overlying non-keratinized squamous cell lining with an atypical cell population in some fragments. Histological features were compatible with a high-grade epithelial tumour like a midline carcinoma, but a final diagnosis of a salivary gland anlage tumour was established. CONCLUSION: Flexible fiber endoscopy is the method of choice for examining the nasal passages and oropharynx in neonates with respiratory distress. Congenital salivary gland anlage tumour is a rare cause of neonatal nasal obstruction; it is benign and complete excision results in a cure. Histologically, it may mimic a malignant tumour owing to the high mitotic index.

Treatment of high risk medulloblastomas in children above the age of 3 years: a SFOP study.

AIM: Improvement of EFS of children older than 3 years with high risk medulloblastoma. METHODS: Between 1993 and 1999, 115 patients (3-18 years, mean 8 years) with high risk medulloblastoma were included. After surgery treatment consisted of chemotherapy ('8in1' and etoposide/carboplatin) before and after craniospinal radiotherapy. RESULTS: Patients were staged using Chang-criteria (PF residue only, M1 and M2/M3) by local investigator as well as by central review panel (82.4% concordance). Chemotherapy was well tolerated without major delays in radiotherapy. With a mean follow up of 81 months (9-119), 5-year EFS was 49.8% and OS 60.1%. In detail according to subgroups EFS was 68.8% for PF residue only, 58.8% for M1 disease and 43.1% for M2/M3. CONCLUSION: M1 patients are legitimate high risk patients. Survival rates are still very low for high risk medulloblastoma patients and future trials should therefore focus on more intensive (chemotherapy/radiotherapy) treatment.

[Aneurysms of the posterior cerebral artery: comparison of a retrospective series of surgically-treated patients with endovascularly-treated patients from the literature]. / Aneurysmata van de arteria cerebri posterior: vergelijking van een historische reeks heel-kundig behandelde patiënten met de endovasculair behandelde patiënten uit de literatuur.

Subarachnoid hemorrhages caused by rupture of an aneurysm of the posterior cerebral artery are very rare. The surgical treatment of these aneurysms by clipping is studied in a retrospective series. Recent data from the literature seem to confirm good results when these aneurysms are treated by endovascular techniques. The results from the surgical series are compared with the results from the endovascular series. The endovascular treatment seems to become more important for the future.

Frequency specific hearing improvement in microvascular decompression of the cochlear nerve.

BACKGROUND: Microvascular compressions of the cochlear nerve can lead to hearing loss. Due to the tonotopic organization of the cochlear nerve any focal compression of the cochlear nerve will result in a frequency specific hearing loss. Decompressing the cochlear nerve could result in a frequency specific hearing improvement, without improving overall hearing. METHOD: Thirty one patients underwent microvascular decompression operations of the vestibulocochlear nerve for vertigo or tinnitus. Preoperative audiograms were substracted from postoperative audiograms obtained 2 years after microvascular decompression. The frequencies of maximal hearing improvement postoperatively were determined. FINDINGS: Of the 31 patients studied, 19 had improvements of 5 dB or more at one or more frequencies postoperatively, and 15 patients had improvements of 10 dB or more. Three patients had improvements of 25 dB or more postoperatively. The postoperative hearing improvement was frequency-specific and related to the anatomical location of the vascular contact on the auditory nerve. The improvement of hearing becomes diluted when the difference between pre- and postoperative hearing thresholds are averaged over all audiometric frequencies. We therefore present results for each frequency that was tested. CONCLUSIONS: Microvascular decompression of the cochlear nerve can improve hearing in selected patients. The improvement seems too small to justify decompressive surgery for the sole purpose of hearing improvement, but it could be considered if associated short vertigo spells, ipsilateral tinnitus, otalgia and cryptogenic hemifacial spasm are present. Decompression should be performed early, before BAEP changes become noticeable. 3D-MRI could become a valuable tool for selecting good surgical candidates.

Image guided surgery for petrous apex lesions.

OBJECTIVES: To evaluate whether computer-assisted frameless stereotactic navigation in the temporal bone provides sufficient clinical application accuracy and thus a useful tool in temporal bone surgery. METHODS: Two patients with petrous apex cholesterol granuloma were operated on by an epidural middle fossa approach using a Stealth/Medtronic trade mark neuronavigation system. Based on literature data optimal skin fiducial placement and registration methods were used. Intra-operative accuracy was checked using three precise anatomical landmarks. Drilling of the petrous apex bone was guided by neuronavigation. Postoperative Computed Tomography (CT) images were fused with the preoperative CT and planning. RESULTS: The application of image-guidance in temporal bone surgery causes no additional burden to the patient nor prolongs the operating time. The accuracy measured at the anatomical landmarks was under 2,0 mm. This is confirmed by evaluation of bone removal through image fusion of pre- and postoperative CT-scan. CONCLUSIONS: The clinical application of a neuronavigation system during petrous apex surgery can be regarded as useful. Using all available data on registration methods it seems possible to obtain intra-operative application accuracies of <2,0 mm. Additional cadaver work is being performed to support these data.

The value of MRI in the diagnosis of postoperative spondylodiscitis.

We evaluated the role of MRI in the diagnosis of postoperative spondylodiscitis. Spondylodiscitis is a serious complication of surgery, and the diagnosis frequently depends on a combination of clinical, laboratory and imaging findings. We compared the MRI findings in six patients with biopsy- or surgery-proven spondylodiscitis with those in 38 asymptomatic postoperative patients. Contrast enhancement and signal changes in the intervertebral disc or the vertebral endplates are not specific for spondylodiscitis, being also seen in the asymptomatic patients. However, absence of Modic type 1 changes, of contrast enhancement of the disc or of enhancing paravertebral soft tissues suggests that the patient does not have spondylodiscitis. MRI appears more useful for exclusion than for confirmation of postoperative spondylodiscitis.

Impaired autoregulation of cerebral blood flow in an experimental model of traumatic brain injury.

In order to study the pathophysiology and the intracranial hemodynamics of traumatic brain injury, we have developed a modified closed-head injury model of impact-acceleration that expresses several features of severe head injury in humans, including acute and long-lasting intracranial hypertension, diffuse axonal injury, neuronal necrosis, bleeding, and edema. In view of the clinical relevance of impaired autoregulation of cerebral blood flow after traumatic brain injury, and aiming at further characterization of the model, we investigated the autoregulation efficiency 24 h after experimental closed-head injury. Cortical blood flow was continuously monitored with a laser-Doppler flowmeter, and the mean arterial blood pressure was progressively decreased by controlled hemorrhage. Relative laser-Doppler flow was plotted against the corresponding mean arterial blood pressure, and a two-line segmented model was applied to determine the break point and slopes of the autoregulation curves. The slope of the curve at the right hand of the break point was significantly increased in the closed head injury group (0.751 +/- 0.966%/mm Hg versus -0.104 +/- 0.425%/mm Hg,p = 0.028). The break point tended towards higher values in the closed head injury group (62.2 +/- 20.8 mm Hg versus 46.9 +/- 12.7 mm Hg; mean +/- SD, p = 0.198). It is concluded that cerebral autoregulation in this modified closed head injury model is impaired 24 h after traumatic brain injury. This finding, in addition to other characteristic features of severe head injury established earlier in this model, significantly contributes to its clinical relevance.

Endocrine consequences of long-term intrathecal administration of opioids.

Intrathecal administration of opioids is a very efficient tool in the long-term control of intractable nonmalignant pain. However, despite the well known role of opioids in endocrine regulation, few data are available about possible effects on hypothalamic-pituitary function during this treatment. Seventy-three patients (29 men and 44 women; mean age, 49.2 +/- 11.7 yr) receiving opioids intrathecally for nonmalignant pain were enrolled for extensive endocrine investigation. At the time of hormonal determination, the mean duration of opioid treatment was 26.6 +/- 16.3 months; the mean daily dose of morphine was 4.8 +/- 3.2 mg. The control group consisted of 20 patients (11 men and 9 women; mean age, 54.2 +/- 14.0 yr) with a comparable pain syndrome but not treated with opioids. Decreased libido or impotency was present in 23 of 24 men receiving opioids. The serum testosterone level was below 9 nmol/L in 25 of 29 men and was significantly lower than that in the control group (P < 0.001). The free androgen index was below normal in 18 of 29 men and was significantly lower than that in the control group (P < 0.001). The serum LH level was less than 2 U/L in 20 of 29 men and was significantly lower than that in the control group (P < 0.001). Serum FSH was comparable in both groups. Decreased libido was present in 22 of 32 women receiving opioids. All 21 premenopausal females developed either amenorrhea or an irregular menstrual cycle, with ovulation in only 1. Serum LH, estradiol, and progesterone levels were lower in the opioid group. In all 18 postmenopausal females significantly decreased serum LH (P < 0.001) and FSH (P = 0.012) levels were found. The 24-h urinary free cortisol excretion was below 20 microg/day in 14 of 71 opioid patients and was significantly lower than that in the control group (P = 0.003). The peak cortisol response to insulin-induced hypoglycemia was below 180 microg/L in 9 of 61 opioid patients and was significantly lower than that in the nonopioid group (P = 0.002). The insulin-like growth factor I SD score was below -2 SD in 12 of 73 opioid patients and was significantly lower than that in the control group (P = 0.002). The peak GH response to hypoglycemia was below 3 microg/L in 9 of 62 subjects and was significantly lower than that in the control group (P = 0.010). Thyroid function tests and PRL levels were considered normal. No metabolic disturbances were recorded, apart from significantly decreased high density lipoprotein cholesterol levels (P = 0.041) and elevated total/high density lipoprotein cholesterol ratio (P = 0.008) in the opioid group compared to the control group. Supplementation with gonadal steroids improved sexual function in most patients. In conclusion, of all patients receiving intrathecal opioids, the large majority of men and all women developed hypogonadotropic hypogonadism, about 15% developed central hypocorticism, and about 15% developed GH deficiency. These findings suggest that further investigations are required to determine the need for systematic endocrine work-up in these patients and the necessity for substitutive therapy.

Validation of a closed head injury model for use in long-term studies.

To study pharmacotherapy of traumatic brain injury in rats, a modified closed head injury model was used that expresses clinically relevant features including intracranial hypertension and morphological alterations. Long-term survival under ethically acceptable conditions would greatly improve its clinical relevance. To ensure this goal with great reproducibility, the experimental protocol was adapted, in particular the impact-acceleration kinetics. Variations in impact-acceleration conditions were obtained by modifying the stiffness of the impact site and changing the height of a 400 g weight dropped from 51.5 to 31.5 cm (51.5/400; 31.5/400). Impact and acceleration were measured with a force sensor incorporated in a rigid dummy-rat and an accelerometer mounted on the platform onto which the animals are positioned. Significant correlation was shown between impact and acceleration. Accelerations obtained in rats were significantly lower than those in the dummy. Unlike the 51.5/400 group, in the 31.5/400 group no mortality or cranial fractures were observed. In both groups intracranial pressure rose to pathological values immediately after trauma and remained elevated longer than 24 h. Diffuse axonal injury developed in all groups and remained present for at least 7 days. By reducing the impact-acceleration conditions, post-traumatic complications were diminished, while the clinically important features were maintained.

Cabergoline in the treatment of hyperprolactinemia: a study in 455 patients.

Cabergoline is a new long-acting dopamine agonist that is very effective and well tolerated in patients with pathological hyperprolactinemia. The aim of this study was to examine, in a very large number of hyperprolactinemic patients, the ability to normalize PRL levels with cabergoline, to determine the effective dose and tolerance, and to assess the effect on clinical symptoms, tumor shrinkage, and visual field abnormalities. We also evaluated the effects of cabergoline in a large subgroup of patients with bromocriptine intolerance or -resistance. We retrospectively reviewed the files of 455 patients (102 males and 353 females) with pathological hyperprolactinemia treated with cabergoline in 9 Belgian centers. Among these patients, 41% had a microadenoma; 42%, a macroadenoma; 16%, idiopathic hyperprolactinemia; and 1%, an empty sella. The median pretreatment serum PRL level was 124 microg/L (range, 16-26,250 microg/L). A subgroup of 292 patients had previously been treated with bromocriptine, of which 140 showed bromocriptine intolerance and 58 showed bromocriptine resistance. Treatment with cabergoline normalized serum PRL levels in 86% of all patients: in 92% of 244 patients with idiopathic hyperprolactinemia or a microprolactinoma and in 77% of 181 macroadenomas. Pretreatment visual field abnormalities normalized in 70% of patients, and tumor shrinkage was seen in 67% of cases. Side effects were noted in 13% of patients, but only 3.9% discontinued therapy because of side effects. The median dose of cabergoline at the start of therapy was 1.0 mg/week but could be reduced to 0.5 mg/week once control was achieved. Patients with a macroprolactinoma needed a higher median cabergoline dose, compared with those with idiopathic hyperprolactinemia or a microprolactinoma: 1.0 mg/week vs. 0.5 mg/week, although a large overlap existed between these groups. Twenty-seven women treated with cabergoline became pregnant, and 25 delivered a healthy child. One patient had an intended abortion and another a miscarriage. In the patients with bromocriptine intolerance, normalization of PRL was reached in 84% of cases, whereas in the bromocriptine-resistant patients, PRL could be normalized in 70%. We confirmed, in a large-scale retrospective study, the high efficacy and tolerability of cabergoline in the treatment of pathological hyperprolactinemia, leaving few patients with unacceptable side effects or inadequate clinical response. Patients with idiopathic hyperprolactinemia or a microprolactinoma, on average, needed only half the dose of cabergoline as those with macroprolactinomas and have a higher chance of obtaining PRL normalization. Cabergoline also normalized PRL in the majority of patients with known bromocriptine intolerance or -resistance. Once PRL secretion was adequately controlled, the dose of cabergoline could often be significantly decreased, which further reduced costs of therapy.

Temporal changes in intracranial pressure in a modified experimental model of closed head injury.

OBJECT: The authors describe an experimental model of closed head injury in rodents that was modified from one developed by Marmarou and colleagues. This modification allows dual control of the dynamic process of impact compared with impulse loading that occurs at the moment of primary brain injury. The principal element in this weight-drop model is an adjustable table that supports the rat at the moment of impact from weights positioned at different heights (accelerations). The aim was to obtain reproducible pathological intracranial pressure (ICPs) while maximally reducing the incidence of mortality and skull fractures. METHODS: Intracranial pressure was investigated in different experimental settings, including two different rat strains and various impact-acceleration conditions and posttrauma survival times. Identical impact-acceleration injuries produced a considerably higher mortality rate in Wistar rats than in Sprague-Dawley rats (50% and 0%, respectively). Gradually increasing severity of impact-acceleration conditions resulted in findings of a significant correlation between the degree of traumatic challenge and increased ICP at 4 hours (p < 0.001, R2=0.73). When the impact-acceleration ratio was changed to result in a more severe head injury, the ICP at 4, 24, and 72 hours was significantly elevated in comparison with that seen in sham-injured rats (4 hours: 19.7+/-2.8 mm Hg, p=0.004; 24 hours: 21.8+/-1.1 mm Hg, p=0.002; 72 hours: 11.9+/-2.5 mm Hg, p=0.009). Comparison of the rise in ICP between moderate and severe impact-acceleration injury at 4 and 24 hours revealed a significantly higher value after severe injury (4 hours: p=0.008; 24 hours: p=0.004). Continuous recordings showed that ICP mounted very rapidly to peak values, which declined gradually toward a pathological level dependent on the severity of the primary insult. Histological examination after severe trauma revealed evidence of irreversible neuronal necrosis, diffuse axonal injury, petechial bleeding, glial swelling, and perivascular edema. CONCLUSIONS: This modified closed head injury model mimics several clinical features of traumatic injury and produces reliable, predictable, and reproducible ICP elevations with concomitant morphological alterations.

Imaging findings in diffuse axonal injury after closed head trauma.

Even in patients with closed head trauma, brain parenchyma can be severely injured due to disruption of axonal fibers by shearing forces during acceleration, deceleration, and rotation of the head. In this article we review the spectrum of imaging findings in patients with diffuse axonal injuries (DAI) after closed head trauma. Knowledge of the location and imaging characteristics of DAI is important to radiologists for detection and diagnosis. Common locations of DAI include: cerebral hemispheric gray-white matter interface and subcortical white matter, body and splenium of corpus callosum, basal ganglia, dorsolateral aspect of brainstem, and cerebellum. In the acute phase, CT may show punctate hemorrhages. The true extent of brain involvement is better appreciated with MR imaging, because both hemorrhagic and non-hemorrhagic lesions (gliotic scars) can be detected. The MR appearance of DAI lesions depends on several factors, including age of injury, presence of hemorrhage or blood-breakdown products (e. g., hemosiderin), and type of sequence used. Technical aspects in MR imaging of these patients are discussed. Non-hemorrhagic lesions can be detected with fluid attenuated inversion recovery (FLAIR), proton-density-, or T2-weighted images, whereas gradient echo sequences with long TE increase the visibility of old hemorrhagic lesions.

Detection of serum insulin-like growth factor binding proteins on western ligand blots by biotinylated IGF and enhanced chemiluminescence.

A novel procedure for the detection of IGF binding capacity of IGFBPs on Western ligand blots (WLB) was developed using biotinylated IGFs as probes. The biotinylated IGF-IGFBP complexes were visualized by streptavidin-horseradish peroxidase and enhanced chemiluminescence (ECL). The procedure was found to be faster and more efficient than the conventional method with iodinated IGFs. In normal human serum a predominant doublet at 38-42 kDa and five smaller bands at 35, 34, 30, 28 and 24 kDa were detected by both methods, whereas two additional bands at 26 and 16 kDa became visible with the ECL method. In pregnancy serum only one single faint band at 30 kDa could be detected by the iodinated method. In contrast, the ECL method revealed five other bands at 42, 34, 28, 26 and 16 kDa. Besides the 38-42 kDa doublet, the 30 and 16 kDa bands reacted strongly with anti-IGFBP-3 antibodies in Western immunoblotting (WIB) and therefore were related to IGFBP-3 fragments. The technical advantages of this ECL method include an extremely short exposure time to the radiographic film and a long stability of the probe. In addition, the ECL method is a non-radioactive method, making radioprotection and radioactive waste removal unnecessary.

125I-Tyr0-hCRH labelling characteristics of corticotropin-releasing hormone receptors: differences between normal and adenomatous corticotrophs.

The presence of corticotropin-releasing hormone (CRH) receptors has been previously demonstrated in corticotrophs from normal pituitaries using a method combining immunocytochemistry and liquid emulsion autoradiography. The aim of this study was to compare the characteristics of the 125I-Tyr0-hCRH binding in corticotrophs from normal pituitaries (three obtained at autopsy and one obtained at surgery) with corticotrophs from pituitary adenomas (six corticotroph adenomas responsible for Cushing's disease and two silent corticotroph adenomas secreting a biologically inactive ACTH molecule). In normal corticotrophs, the larger part of the 125I-Tyr0-hCRH binding was localised in patchy conglomerates at the centre of the cell and, to a much lesser degree, in a diffuse pattern at the cell periphery. In adenomatous corticotrophs, CRH receptor expression is disturbed both quantitatively and qualitatively. Except for a minority of cells in one adenoma, all adenomatous corticotrophs showed only peripherally bound 125I-Tyr0-hCRH and no centrally localised binding. Furthermore, adenomatous corticotrophs revealed a statistically significant lower signal intensity when compared to normal corticotrophs and a strongly negative correlation was found between the labelling area in adenomatous corticotrophs and both the basal and CRH-stimulated plasma ACTH levels. These findings suggest defective processing of CRH receptors and could be relevant to the sustained ACTH secretion by adenomatous corticotrophs in Cushing's disease and, more generally, provide an explanation to its pathology. The silent corticotrophs secreting a biologically inactive ACTH molecule were characterised by a very faint signal intensity, although present on almost every cell.

Selective vestibular neurectomy in Menière's disease: a review.

A review of the literature on selective vestibular neurectomy for Meniere's disease is presented. The procedure is placed in historical context and current refinements of the technique are highlighted. In particular, the different methods of evaluating results on vertigo, hearing, tinnitus, aural pressure and imbalance are summarised. The controversy over the indication, timing and outcome measures for selective vestibular neurectomy is discussed. In experienced hands there appears to be a low complication rate, emphasising the value of this procedure in relieving intractable vertigo when a destructive procedure is indicated.

Intracranial pressure in a modified experimental model of closed head injury.

Intracranial pressure (ICP) was studied in a modified experimental model of closed head injury, in which the dynamic process of impact versus impulse loading was separately controlled. In this model, mortality of Wistar rats was considerably higher as compared to Sprague-Dawley rats subjected to similar traumatic conditions. Therefore Sprague-Dawley rats were used for all further experiments. Twenty-four rats, divided into 4 groups, underwent either sham or gradually increasing impact-acceleration trauma. Four hours after closed head injury, ICP measurements showed a significant correlation between the severity of the traumatic challenge and the resultant pressure rise (r2 = 0.731; p < 0.001). At the moment of impact there was a momentary blood pressure peak immediately followed by a transient period of hypotension. ICP measurements following directly to an impact-acceleration trauma, revealed an abrupt rise in ICP reaching pathological levels within 5 minutes. In conclusion, this modified model of closed head injury produces a predictable and reproducible pathologic ICP in Sprague-Dawley rats.

Early postoperative gadolinium-DTPA-enhanced MR imaging after successful lumbar discectomy.

A prospective study was undertaken to establish the normal spectrum of early gadolinium-enhanced magnetic resonance (MR) imaging findings in patients who had resolution of symptoms after lumbar discectomy. Thirty-four patients underwent MR examinations 6 weeks and 6 months after lumbar discectomy on a 1.5 T superconducting unit, including sagittal and axial spin-echo (SE) T1-weighted images before and after intravenous administration of gadolinium-DTPA, as well as sagittal turbo (or fast-) SE T2-weighted images. All patients showed soft tissue enhancement along the surgical track in the subcutaneous soft tissue lateral to the spinous process and in the epidural space. There was only minimal (45%) or no (55%) mass effect on the dural sac associated with epidural scar formation 6 months after surgery, but often the nerve root at the operative level was surrounded by this enhancing tissue. Facet joint enhancement was seen in most patients 6 weeks (63%) and 6 months (53%) after surgery. Intrathecal nerve root enhancement was observed in six patients, 6 weeks after surgery. Nine patients (20%) had residual mass effect on the neural elements with an enhancement pattern suggestive of a disc fragment. Enhancement of the intervertebral space was seen in 67% of patients 6 weeks after surgery and in 86% of patients after 6 months. It may be concluded that, despite the use of gadolinium-DTPA, MR studies obtained in the initial postoperative period are difficult to interpret, because of the normal sequence of changes. Consequently, the clinical picture still remains the major indicator for recurrent surgery.

Instability of microsatellites in human gliomas.

We have analyzed DNA obtained from 10 glioblastomas multiforme and 6 astrocytomas for microsatellite instability, using 17 different microsatellite loci dispersed over 7 different chromosomes. Six of 16 gliomas showed 1 or more microsatellite alterations in tumor DNA as compared to constitutional DNA. We observed microsatellite instability resulting in allelic shifts in 5 of 10 glioblastomas multiforme but not in any of the astrocytomas. Loss of an allele was observed in 3 glioblastomas multiforme. An imbalance in the intensity of alleles was noticed in 1 astrocytoma and in 1 glioblastoma multiforme. In 1 glioblastoma multiforme, an extra allele was present at two distinct loci. Overall, 5.3% of microsatellite analyses showed an abnormality. We conclude that microsatellite instability is present at a low grade in glioblastomas multiforme but to a lesser extent in astrocytomas. Genomic instability in human gliomas, therefore, should not be regarded as a mechanism for tumor initiation but as an evolution in tumor progression.

Pituitary metastasis mimicking a pituitary adenoma. A description of two cases.

The cases of two elderly women treated for temporal hemianopsia due to a large pituitary mass with suprasellar extension are presented. In both cases, the clinical picture, without diabetes insipidus and cranial nerve paralysis, as well the neuroimaging and endocrinological investigation showing hypopituitarism, were suggestive of a non-secreting pituitary adenoma. In the first patient malignant tissue was unexpectedly encountered during transsphenoidal surgery. Anatomopathological investigation confirmed the presence of a metastasis of a breast carcinoma for which she had been treated 17 years earlier. In the second patient, a preoperative chest X-ray before transsphenoidal surgery revealed an asymptomatic bronchial tumour. Subsequently a squamous cell carcinoma with a metastasis in the pituitary was confirmed. These two cases illustrate the fact that a pituitary metastasis can closely mimic a pituitary adenoma. Even in the absence of suggestive symptoms such as diabetes insipidus and/or cranial nerve paralysis the possibility of metastatic disease in the differential diagnosis of a pituitary mass should always be considered.