Pregnancy and Delivery in Women with Lower Urinary Tract Reconstruction: A National Multicenter Retrospective Study from the French-Speaking Neuro-Urology Study Group (GENULF) and the Neuro-Urology Committee of the French Association of Urology.

PURPOSE: Management of pregnancy and delivery in women with lower urinary tract reconstruction is challenging and the currently available literature is insufficient to guide clinical practice. We report pregnancy and delivery outcomes in this specific population. MATERIALS AND METHODS: We conducted a national multicenter retrospective study (16 centers) including 68 women with 96 deliveries between 1998 and 2019. These women had at least 1 successful pregnancy and delivery after augmentation enterocystoplasty, catheterizable channel creation and/or artificial urinary sphincter implantation. Maternal and fetal complications during pregnancy and delivery were reported, as well as postpartum functional outcomes, according to the delivery mode. The chi-square test and Student's t-test were used to compare categorical and continuous variables, respectively. RESULTS: Overall 32% of reported pregnancies were complicated by febrile urinary tract infections, 13.5% by renal colic and 14.6% required upper urinary tract diversion. In addition, 10% of patients reported transient self-catheterization difficulties and 13.5% reported de novo or increased urinary incontinence. The preterm delivery rate was 35.3%. Elective C-section was performed in 61% of pregnancies. Twenty complications occurred during delivery (20%), including 19 during elective C-section. Urinary continence at 1 year was unchanged for 93.5% of deliveries. Delivery mode (p=0.293) and multiparity (p=0.572) had no impact on urinary continence. CONCLUSIONS: In this population C-section appeared to be associated with a high risk of complications. In the absence of any obstetric or neurological contraindications, vaginal delivery should be proposed as the first line option to the majority of these women.

[Nontumoral epileptogenic lesions]. / Les lésions épileptogènes non tumorales.

Nontumoral epileptogenic lesions account for the major pathological group of surgical specimens obtained from patients with temporal or extratemporal drug-resistant epilepsy. Hippocampal sclerosis remains the predominant etiology, but cerebral cortical dysplasias actually make up the second major cause of nontumoral epilepsy and are increasingly recognized. The percentage of vascular lesions or glial/glio-mesodermal scars remains stable, but the minor or nonspecific lesion group is decreasing because of imaging investigation technique improvement.

[A rare lesion of the central nervous system: inflammatory pseudotumor]. / Une lésion rare du système nerveux central: la pseudotumeur inflammatoire.

Inflammatory pseudotumor is an uncommon tumor, initially described in the lung, but which can involve various organs. It is a controversial entity. We report the case of a 19-year-old-man with an inflammatory pseudotumor localized in the central nervous system, revealed by epilepsy. Characteristically, the inflammatory pseudotumor is an inflammatory mass leading to manifestations related to its localization. Relatively ubiquitous, this tumor is seldom described in the central nervous system. This uncommon lesion is part of a heterogeneous group of entities which are difficult to diagnose for both surgical pathologists and clinicians.

[Surgical resection of focal cortical dysplasias in the central region]. / Chirurgie des dysplasies corticales focales en région centrale.

BACKGROUND AND PURPOSE: Taylor-type focal cortical dysplasias (TTFCD) represent a particular pathological entity responsible for severe drug-resistant epilepsy of extratemporal location. Epilepsy can be surgically cured if complete removal of the lesion can be performed. However, identification on imaging may be difficult and negative standard MRIs are not rare. The frequent location of TTFCD in the central region restrains the possibilities of complete resection. We report a series of patients operated on for intractable epilepsy associated with TTFCD in the central area. PATIENTS AND METHODS: Between 2000 and 2006, of 34 consecutive patients with TTFCD, 17 had a lesion located in the central area. MRI was considered normal in eight, although in five a subtle gyral abnormality was disclosed on further analysis. A (18)FDG PET scan performed in 16 cases demonstrated focal hypometabolism in 15 that correlated with abnormalities on MRI when visible. SEEG performed in 13 cases revealed typical abnormalities for TTFCD in 10 cases. At resection, cortical and subcortical stimulations of the dysplastic cortex did not elicit a motor response. RESULTS: Postoperative motor or sensory deficit was observed in 13 patients--severe in four--which subsequently resolved completely in seven. Six patients had a minor permanent, motor or sensory deficit. Four patients were reoperated for seizure recurrence and residual dysplastic tissue was found at reoperation in three cases. Average postoperative follow-up was 3.7 years. Sixteen patients (94%) were in Engel Class I (65% in Class IA). CONCLUSION: This study suggests that surgical resection of central region TTFCD may be associated with favorable seizure outcome and no or minor functional permanent disability. In cases of seizure relapse, reoperation can be performed without further permanent deficit and lead to seizure-free outcome. Future techniques for intraoperative detection of these lesions could optimize their complete resection in functional areas.

Self-sufficient biosynthesis of pregnenolone and progesterone in engineered yeast.

The first two steps of the steroidogenic pathway were reproduced in Saccharomyces cerevisiae. Engineering of sterol biosynthesis by disruption of the delta 22-desaturase gene and introduction of the Arabidopsis thaliana delta 7-reductase activity and coexpression of bovine side chain cleavage cytochrome P450, adrenodoxin, and adrenodoxin reductase, lead to pregnenolone biosynthesis from a simple carbon source. Following additional coexpression of human 3 beta-hydroxysteroid dehydrogenase/isomerase, pregnenolone is further metabolized to progesterone. Steroid formation appears to be coupled to yeast sterol biosynthesis.

Exoproteomics of Pathogens: Analysis of Toxins and Other Virulence Factors by Proteomics.

Pathogens are known to release in their environment a large range of toxins and other virulence factors. Their pathogenicity relies on this arsenal of exoproteins and their orchestrated release upon changing environmental conditions. Exoproteomics aims at describing and quantifying the proteins found outside of the cells, thus takes advantage of the most recent methodologies of next-generation proteomics. This approach has been applied with great success to a variety of pathogens increasing the fundamental knowledge on pathogenicity. In this chapter, we describe how the exoproteome should be prepared and handled for high-throughput identification of exoproteins and their quantitation by label-free shotgun proteomics. We also mentioned some bioinformatics tools for extracting information such as toxin similarity search.

[Sentinel node mapping in anorectal melanoma]. / Ganglion sentinelle et mélanome malin anorectal.

Anorectal melanoma is a rare condition and its surgical management is controversial. This article reports the case of a patient with anorectal melanoma who underwent abdominoperineal resection and Sentinel Lymph Node biopsy. Melanoma was classified pT4aN0. Fifty months after initial treatment, the patient is still alive disease free. SLN mapping allows better surgical excision of the presumed sites of the lymphatic dissemination in melanoma. SLN biopsy improve the accuracy of nodal staging. In case of sentinel node metastasis, it allows early therapeutic lymphadenectomy of the sentinel nodes's basin and could therefore reduce the high rate of regional recurrence in anorectal melanoma. Moreover, knowing the exact histological status of the regional nodes means that the relative merits of abdominoperineal resection and wild local excision could be compared in relation to tumor thickness.

Functional endothelin ET B receptors are selectively expressed in human oligodendrogliomas.

Endothelin-1 (ET-1), a vasoactive and mitogenic peptide mainly produced by vascular endothelial cells, may be involved in the progression of several human tumors. Here, we present an immunohistochemical analysis of the expression pattern of ET-1 receptor subtypes (ET(A)-R and ET(B)-R) and a functional study of their potential role in human oligodendrogliomas and oligoastrocytomas. By comparison, we assessed the corresponding expression patterns of glioblastomas. Interestingly, a nuclear localization of ET-1 receptor subtypes (associated or not with a cytoplasmic labeling) was constantly observed in tumor cells from all three glioma types. Moreover, we noted a distinct receptor distribution in the different gliomas: a nuclear expression of ET(B)-R by tumor cells was found to be restricted to oligodendrogliomas and oligoastrocytomas, while a nuclear expression of ET(A)-R was only detected in tumor cells from some glioblastomas. Using primary cultures of oligodendroglial tumor cells, we confirmed the selective expression of nuclear ET(B)-R, together with a plasma membrane expression, and further demonstrated that this receptor was functionally coupled to intracellular signaling pathways known to be involved in cell survival and/or proliferation: extracellular signal-regulated kinase and focal adhesion kinase activation, actin cytoskeleton reorganization. In addition, impairment of ET(B)-R activation in these cells by in vitro treatment with an ET(B)-R-specific antagonist induced cell death. These data point to ET-1 as a possible survival factor for oligodendrogliomas via ET(B)-R activation and suggest that ET(B)-R-specific antagonists might constitute a potential therapeutic alternative for oligodendrogliomas.

[Criteria of diagnosis and grading of oligodendrogliomas or oligo-astrocytomas according to the WHO and Sainte-Anne classifications]. / Oligodendrogliomes et oligo-astrocytomes critères diagnostiques et grading de malignité selon l'OMS et l'hôpital Sainte-Anne.

Two main classification systems are used in France for the histological typing and grading of oligodendrogliomas: the WHO and Sainte-Anne Hospital (SA) classifications. According to the WHO, the typing of diffuse gliomas is based on the predominant cell type, oligodendroglial versus astrocytic. In contrast, the SA classification is based on the distinction of two patterns of tumor growth, solid tumor tissue versus isolated tumor cells and also relies on imaging and clinical features. According to this approach, the SA classification includes in the category of oligodendrogliomas, the fibrillary or gemistocytic diffuse astrocytomas (WHO grade II) as well as a substantial proportion of astrocytomas WHO grade III, 2) the WHO uses multiple histological criteria for the grading of oligodendrogliomas (grade II versus grade III), including the degree of differentiation, cellular atypia, mitotic activity and necrosis. In contrast, the SA grading of these tumors (grade A versus B) only uses two criteria: the presence or absence of endothelial hyperplasia, and the presence or absence of contrast enhancement. This last criterion allows overcoming the problems related to the representativeness of surgical samples. Difficulties and discrepancies regarding the diagnosis of oligodendrogliomas are in part due to the lack of immunomarker for the identification of tumoral oligodendrocytes. The potential interest of new markers of oligodendroglial precursors for the diagnosis of these tumors will further be discussed.

[Reappraisal of the Sainte-Anne Hospital classification of oligodendrogliomas in view of retrospective studies]. / Classification des oligodendrogliomes de l'hôpital Sainte-Anne. Mise au point à l'usage des études rétrospectives.

PURPOSE: Definition of homogeneous tumor groups of oligodendrogliomas or oligo-astrocytomas is a basic condition for an adequate evaluation and comparison of the results of treatments in patients from various institutions. However, increasing discordances are observed in the histological diagnosis of these tumors. The main goal of this study is to assess whether, for retrospective studies, MRI data may serve as a common basis for encompassing asymmetry in diagnosis established according to the WHO or Ste-Anne (SA) classification. PATIENTS AND METHODS: This study included 251 adult patients in whom a SA grade A or B oligodendroglioma or oligo-astrocytoma was newly diagnosed at our institution from 1984 to 2003. Routine histological preparations and post-contrast preoperative MRI/CT-scan were simultaneously reviewed in order to assess the impact on survival of the following features: presence or absence of a polymorphous or gemistocytic astrocytic component, of necrosis and of contrast enhancement (CH); endothelial hyperplasia (EH) assessed as absent, present minor (HE+) or (HE++) when conform to the threshold of HE defined in the SA grading system of oligodendrogliomas. The tumors were graded A: no CH and no EH; in B: CH and /or HE++, and A/B: EH + but no CE. RESULTS: 70.1% of the tumors were classified as "pure" oligodendroglioma, 19.5% as "polymorphous oligo-astroastrocytoma" and 10.3% as "gemistocytic oligo-astrocytoma". In grade A, or B tumors, the presence of a polymorphous or a gemistocytic component had no significant influence on survival; however respectively 53% and 65% of these tumours versus 32% of "pure" oligodendrogliomas were grade B at the time of diagnosis. In either histological subtypes, survival was not significantly different when HE was absent or minor (HE+). After regrouping of the histological subtypes and of the tumors with HE+ or absent, the series included 153 oligodendrogliomas grade A and 98 grade B. Survival in patients with grade A versus grade B tumors was respectively 142 versus 52 months (p<0.0001). In grade B tumors, necrosis had no significant influence on survival. Ring-shaped contrast enhancement surrounding large foci of necrosis was observed in only 4 cases. In tumors with or without CE, patient survival was respectively 148 versus 40 months (p<0.0001). On post contrast MRI done in 235 patients, only 7 tumors (3%) were grade A/B (EH++ but no CH). CONCLUSIONS: From these results and our previous observation that, according to the SA classification of gliomas, only oligodendrogliomas or oligo-astrocytomas may not show CE, we propose that for retrospective studies: 1) tumors diagnosed according to the Ste-Anne classification as oligodendroglioma or oligo-astrocytoma be regrouped in a unique category, 2) independent of their histological type and grade according to the WHO, gliomas that do not show CE be regrouped with SA oligodendrogliomas grade A, 3) concerning gliomas that show CE on MRI: oligodendrogliomas or oligo-astrocytomas WHO grade II or III, as well as WHO secondary glioblastomas or glioblastomas with an oligodendroglial component, be regrouped with SA oligodendrogliomas grade B; however tumors that show ring-like CE surrounding large foci of necrosis and finger-like "peritumoral" edema should be excluded or analysed separately.

[Spatial delimitation of low grade oligodendrogliomas]. / Délimitation spatiale des oligodendrogliomes de bas grade.

Image-guided surgery is the central element of therapeutic management of low grade gliomas and consequently, a precise preoperative definition of their spatial extension is necessary. The question of the present work is: do the imaging abnormalities delineate the real spatial development of low grade oligodendrogliomas? A review of the literature showed that MRI on T2-weighted and FLAIR sequences are used to delineate the spatial developement of these tumours and that spectroscopic magnetic resonance imaging is more sensible to appreciate it. Moreover, mathematical models and histological studies suggest that MRI does not indicate the actual spatial extension of low grade oligodendrogliomas. This study focused on histological analysis of biopsy samples performed outside MRI imaging abnormalities in patients who harboured a low grade oligodendroglioma. It showed that isolated tumour cells were identified beyond imaging abnormalities in all of the 17 patients studied. In 15 of those 17 patients, isolated tumour cells were identified in the most distant biopsy samples taken outside imaging abnormalities. Thus, conventional imaging findings, including MRI on T2-weighted and FLAIR sequences, are not able to provide the real spatial development and boundaries of low grade oligodendrogliomas.

[Oligodendrogliomas: historical background of classifications]. / Oligodendrogliomes: historique des classifications.

The story of the classifications for gliomas is related to the development of the techniques used for cytological and histological examination of brain parenchyma. After a review of these techniques and the progressive discovery of the central nervous system cell types, the main classifications are presented. The first classification is due to Bailey and Cushing in 1926. It was based on histoembryogenetic theory. Then Kernohan introduced, in 1938, the concept of anaplasia. The WHO classification was published in 1979, then revised in 1993 and 2000. It took into account some data from both previous systems and introduced gradually the notion of histological criteria of malignancy. More recently; molecular genetics data and clinical evolution were retained. The Sainte-Anne classification for oligodendrogliomas is based on both histological and imaging data. It includes the notion of spatial histological structure of oligodendrogliomas. Contrast enhancement is closely related to endotheliocapillary hyperplasia. Gliomas classifications are changing and confusions can be made because of lack of reproductibility and misinterpretations of samples.

[Results of the Sainte-Anne - Lyons series of 318 oligodendroglioma in adults]. / Résultats de la série Sainte-Anne - Lyon de 318 oligodendrogliomes intracrâniens de l'adulte.

INTRODUCTION: Incidence of cerebral oligodendrogliomas is increasing because of better recognition made possible by improved classifications. We studied a homogeneous series using the Sainte-Anne grading scale in order to better understanding the history of these tumors with or without treatment and to assess prognosis and associated factors. PATIENTS AND METHODS: A retrospective series of 318 adult patients with oligodendroglioma (OLG) treated at Hôpital Sainte-Anne, Paris (SA) and Hôpital Neurologique, Lyons (L) between 1984 and 2003 was analyzed: 182 grade A OLG (SA + L), 136 grade B among which a homogenous series of 98 (SA) were included. For grade A: age at diagnosis ranged from 21 to 70 (mean: 41), sex ratio was 1.28. For grade B: age at diagnosis ranged from 12 to 75 (mean: 45.5), sex-ratio was 1.58. The main first symptoms were: epilepsy (A: 91.5%; B: 76%), intracranial hypertension (A: 7.9%; B: 14.6%), neurological deficit (A: 5.1%; B: 17.7%). The most frequent locations were: frontal, insular and central for both A and B. Mean size was 55 mm for grade A, 62 mm for B. Calcifications were found in 20% of A, 48.5% of B. No tumor was enhanced on imaging (CT/MRI) in grade A, all but 7 in grade B. All patients underwent surgery either for biopsy (A: 47.2%; B: 53%), or removal which was partial (A: 26.4% vs B: 19.4%) or extended (A: 36.3% vs B: 37.8%). Fifty-six patients underwent 2 procedures and 12 three procedures. Radiotherapy was performed in 76.9% of grade A, and 91% of B patients, in the immediate postoperative period for 71% A and 82.7% B. Chemotherapy was delivered for 36% of grade A (in the event of transformation to grade B or failure of radiotherapy) and 67.5% of B patients. Among grade A tumors, 38% transformed into grade B within a mean delay of 51 months with a mean follow-up of 78 months. RESULTS: Median survival was 136 months for grade A and 52 for grade B. Survival at 5, 10 and 15 was 75.5%, 51% and 22.4% for grade A vs 45.2%, 31.3% and 0% for grade B respectively. In univariate and multivariate analysis, grade A survival was associated with age at diagnosis, tumor size, large removal and response to radiotherapy. Grade B survival was associated with age at diagnosis, wide removal and sharply defined limits of the tumor on imaging. CONCLUSIONS: Analysis of both published data and this series underlines many prognostic parameters. It shows that OLG are heterogeneous tumors even in each grade (A and B). Treatment should consequently progress towards more targeted procedures for patients mainly with postoperative radiotherapy and chemotherapy.

Dysembryoplastic neuroepithelial tumours.

Dysembryoplastic neuroepithelial tumours (DNTs) are a group of supratentorial cortical benignant lesions that superficially resemble mixed oligo-astrocytomas, oligodendrogliomas or astrocytomas. Clinically these tumours are associated with partial seizures beginning before the age of 20 years, with no neurologic deficit and no stigmata of phacomatosis. In the revised WHO classification, DNTs have been incorporated among the category of neuronal and mixed neuronoglial tumours. This classification describes a histologic variant characterized by the following criteria: cortical location, multinodular architecture--the nodule being made of multiple variants looking like astrocytomas, oligodendrogliomas or oligo-astrocytomas, foci of dysplastic cortical disorganization and the presence of a glioneuronal element showing a columnar structure perpendicular to the cortical surface. A study of 14 cases for which only a specific glioneuronal element could be identified demonstrated that this specific element is sufficient for diagnosing DNTs and that the spectrum of DNTs includes a simple form with a unique glioneuronal element. Preoperative imaging follow-up data, in the series of 23 simple and complex forms, indicated that DNTs are perfectly stable. However, these tumours may show a high MIB 1 labeling index.

A new gene expression system based on a fructose-dependent promoter from Rhodobacter capsulatus.

Translational lacZ fusions were constructed to analyse transcription of the fructose operon, encoding the fructose-specific phosphotransferase system of Rhodobacter capsulatus. It was demonstrated that transcription from the fru promoter (fruP) was negligible without fructose, and stimulated more than 100-fold by the presence of the inducer. A multiple cloning site, fruP, and a cassette conferring gentamycin resistance were assembled to form a cloning cartridge which is easily transferable to a broad-host-range vector. The sequence initiating the first gene of the fru operon was altered to introduce a NdeI site, allowing insertion of the 5' end of a gene at the correct distance from the ribosome-binding site. The system has been used to express the Escherichia coli lacZ gene in R. capsulatus. beta Gal activity was shown to be specifically and rapidly induced by fructose, at low concentrations. Vectors for fructose-dependent gene expression also proved to be useful in the complementation analysis of mutants. A fdxN mutant of R. capsulatus, markedly impaired in its ability to fix nitrogen due to the lack of a ferredoxin, could be fully complemented using a plasmid carrying a copy of fdxN behind fruP. Complementation, as well as the synthesis of the ferredoxin, were found to be strictly fructose dependent.

Postoperative radiotherapy of supratentorial low-grade gliomas.

Forty-nine patients with supratentorial low-grade gliomas underwent surgery (biopsy or subtotal resection) and postoperative radiotherapy at the Mayo Clinic between 1976 and 1983. The median, 5-, and 10-year overall survivals for the total group were 6.5 years, 62%, and 14%, respectively. Nine prognostic variables were examined for their possible association with survival, including age, sex, site, size, CT enhancement, histologic type, extent of resection, radiation volume, and radiation dose. Of these variables, only histologic type was significantly associated with survival. The estimated 5-year survival was 100% for the 5 patients with pilocytic astrocytomas, 83% for the 20 patients with oligodendrogliomas or mixed oligo-astrocytomas, and 40% in the 24 patients with ordinary astrocytomas (log rank p = 0.001). Other possible prognostic variables, such as radiation volume or total dose, showed no association with survival. Twenty-seven patients had a documented treatment failure. For the 20 patients in whom the pattern of failure could be determined, all failed within their radiation portals. Eleven patients had additional tissue obtained following suspected disease recurrence. Tumor was found in ten of these patients, and radionecrosis in one.

Central neurocytomas. Critical evaluation of a small-cell neuronal tumor.

We report herein the clinical and pathological features of 20 patients with central neurocytomas. Investigations for various differentiation antigens and cell type-specific markers were performed by immunohistochemistry using paraffin-embedded tissue. In addition, the expression of L1 adhesion molecule and of the various N.CAM (neural cell adhesion molecule) isoforms were investigated by immunoblotting studies in two frozen specimens. Central neurocytomas are clinically characterized by their intraventricular localization, occurrence in young adults, and good prognosis. It rarely occurs in patients over 50, but such cases have a poor prognosis. Total surgical excision is the best treatment. Radiotherapy is appropriate if surgery is incomplete or contraindicated. Histologically, central neurocytomas display the following features: an oligo-like pattern, usually associated with large fibrillary rosettes or perivascular arrangement, and a rich endocrine-type vasculature. Central neurocytomas have a remarkably homogeneous antigenic profile. GFAP expression is only found in scattered reactive astrocytes, S100 protein in reactive astrocytes and rare tumor cells. Among the pan-neuroendocrine markers, central neurocytomas always express neuron-specific enolase; they frequently express synaptophysin but never chromogranin A. Synaptophysin is the most reliable immunohistological marker for central neurocytomas; however, immunoreactivity could be lost with long formalin fixation. In these cases, electron microscopy is used to support the neuronal nature of the tumor cells. The expression of L1 adhesion molecule and the isoform 180 of N.CAM, indicates that central neurocytomas are formed by cells committed to neuronal phenotype. Nevertheless, advanced neuronal differentiation may be absent, as suggested by the persistence of embryonic N.CAM, the nonexpression of neurofilament proteins, and the absence of mature synapses in numerous cases. Central neurocytomas and neuroblastomas share some biochemical properties, but their respective clinicopathological features and biological behavior are dramatically different.

A histologic and cytologic method for the spatial definition of gliomas.

Because of the increasing application of stereotactic neurosurgical techniques not only in the diagnosis but also in the treatment of brain tumors, a demand for data regarding the spatial delimitation of gliomas is being created. Traditional histologic criteria were not established for detecting isolated tumor cells located at the boundaries of gliomas. Standard histologic techniques used for processing surgical specimens result in preparations of insufficient quality to allow the detection of minimal tumor infiltrates within normal brain parenchyma. Consequently, histologic examination has been considered an unreliable method of determining the boundaries of gliomas. In this study, we describe in detail an improved technique of biopsy specimen preparation that involves the use of glutaraldehyde-fixed and hemalum-phloxine-stained paraffin sections as well as alcohol-fixed and hemalum-phloxine-stained smears. In concert, these methods allow visualization of delicate cytologic details and are complementary in assessing the presence of isolated tumor cells at the periphery of gliomas. We define morphologic criteria for the accurate identification of isolated neoplastic cells and for their distinction from normal or reactive glial elements. These morphologic criteria include classic cytologic features of malignant lesions (such as nuclear pleomorphism and hyperchromasia) as well as the assessment of tumor architecture and cellular spatial relationships.

Stereotactic histologic correlations of computed tomography- and magnetic resonance imaging-defined abnormalities in patients with glial neoplasms.

In 39 patients who harbored previously untreated astrocytomas (21 patients), oligoastrocytomas (9 patients), or oligodendrogliomas (9 patients), computed tomographic (CT) and magnetic resonance imaging (MRI) findings were correlated with stereotactic serial biopsy findings. The 39 patients were classified as having one of three types of tumor: type I (1 patient), which consisted only of circumscribed tumor tissue; type II (26 patients), which consisted of tumor tissue and isolated tumor cells; or type III (11 patients), which consisted of intact parenchyma infiltrated by isolated tumor cells. (In one patient, the biopsy sampling was inadequate for determining the type of tumor.) In high-grade lesions, tumor tissue was obtained from CT contrast-enhancing regions, and the area of enhancement accurately defined the tumor tissue volume. In low-grade lesions, tumor tissue was hypodense and indistinguishable from parenchyma infiltrated by isolated tumor cells on both CT and MRI. Isolated tumor cells usually extended as far as the prolongation of T2 on T2-weighted MRI of high-grade and low-grade tumors. CT and MRI detection of boundaries and stereotactic serial biopsies are necessary for the demarcation of glial neoplasms into tumor tissue and isolated tumor cell volumes as well as for the determination of the spatial extent of each component. This information is important for determining appropriate treatment.

Comparison of somatostatin receptor expression in human gliomas and medulloblastomas.

The expression of the five somatostatin receptor subtypes, sst1-5 was compared on tissue containing glial tumours (glioblastomas or oligodendrogliomas), medulloblastomas, and on normal human cortex. By semiquantitative reverse transcription coupled to polymerase chain reaction, the receptor expression profiles were high in cortex and in tissue containing oligodendrogliomas. It was moderate in medulloblastomas. Tissue containing glioblastomas displayed lower expression of somatostatin receptor subtypes, sst1 and sst3 being mostly expressed. By 125I-Tyr0DTrp8 somatostatin-14 or 125I-Leu8DTrp22 Tyr25 somatostatin-28 autoradiography combined with synaptophysin immunohistochemistry, it was possible to differentiate between isolated tumoral cell component infiltrating the cerebral parenchyma (cortex or white matter) and tumoral tissue (without residual parenchyma) in glioblastomas or oligodendrogliomas. Glial tumoral tissue per se presented few somatostatin receptors. By contrast, medulloblastoma tumoral cells exhibited numerous octreotide sensitive somatostatin receptors. sst2 immunocytochemistry demonstrated immunostaining of neuronal cells and neuropile; sst2 and sst3 immunostaining was identified on glioblastoma proliferating vessels endothelial cells and on medulloblastomas tumoral cells. Faint sst2 immunostaining among glial tumoral cells was due to microglia, while glioma cells did not significantly stain. In summary, medulloblastoma tumoral cells express sst2/sst3 receptors at a high level while glioma cells do not. In gliomas, sst expression is restricted to endothelial cells on proliferating vessels (displaying both sst2 and sst3 receptors), including parenchyma and reactive microglia (only sst2). The differential expression of sst2/sst3 receptors on gliomas and medulloblastomas has implications for the therapy of these tumours.