Tectal plate tumours. Our experience with a paediatric surgical series

INTRODUCTION

Exophytic tectal plate tumours are a particular kind of brain stem tumour that can be treated with microsurgical resection. This paper reports our surgical experience with a paediatric series stressing and underlines the fact that this surgery can be possible because the rate of surgical mortality is low in experienced hands with acceptable morbidity.

MATERIAL AND METHODS

From 1997 to 2010, 27 patients were treated for exophytic tectal plate tumours. The clinical symptomatology was characterized by an intracranial hypertensive syndrome in 77% of cases, visual disorders in 36% of cases and a Parinaud's syndrome in 12% of cases. All patients were studied using a pre-operative cranio-spinal MRI with and without gadolinium. Hydrocephalus was present in 20 cases treated with a VP shunt in 6 cases and an ETV in the other cases. The surgical removal was total in 60% of cases, partial in 28% of cases and only a large biopsy in 12% of cases. From an histological point of view benign gliomas were diagnosed in 84% of cases and in 16% of cases were classified as WHO grade II and III. Eight patients needed complementary treatment, four with chemotherapy and four with chemotherapy associated to radiotherapy. As a surgical complication two patients had hydrocephalus, one patient had a sub-dural acute haematoma, two patients had an infectious complication requiring surgical treatment and antibiotic therapy, and 5 patients a mechanical shunt dysfunction. No post-surgical mortality was observed.

RESULTS

The most recent results after a median survival of 4.3 years show that 22 patients are still alive while 5 patients died of a progressive disease. Twenty patients in school age continue to follow a normal school programme but 10 patients need assistance.

CONCLUSION

Exophytic tectal plate tumours can be treated based on a microsurgical approach in paediatric patients. In experienced hands surgery can be performed with an acceptable morbidity and with zero percent mortality. In our experience, the sub-occipital transtentorial approach permits a wide view of the region and safe surgical removal.

Histopathology of pineal germ cell tumors

Germ cell tumors (GCTs) classically occur in gonads. However, they are the most frequent neoplasms in the pineal region. The pineal location of GCTs may be caused by the neoplastic transformation of a primordial germ cell that has mismigrated. The World Health Organization (WHO) recognizes 5 histological types of intracranial GCTs: germinoma and non-germinomatous tumors including embryonal carcinoma, yolk sac tumor, choriocarcinoma and mature or immature teratoma. Germinomas and teratomas are frequently encountered as pure tumors whereas the other types are mostly part of mixed GCTs. In this situation, the neuropathologist has to be able to identify each component of a GCT. When diagnosis is difficult, use of recent immunohistochemical markers such as OCT(octamer-binding transcription factor)3/4, Glypican 3, SALL(sal-like protein)4 may be required. OCT3/4 is helpful in the diagnosis of germinomas, Glypican 3 in the diagnosis of yolk sac tumors and SALL4 in the diagnosis of the germ cell nature of an intracranial tumor. When the germ cell nature of a pineal tumor is doubtful, the finding of an isochromosome 12p suggests the diagnosis of GCT. The final pathological report should always be confronted with the clinical data, especially the serum or cerebrospinal fluid levels of β-human chorionic gonadotropin (HCG) and alpha-fetoprotein.

Papillary tumor of the pineal region: Histopathological characterization and review of the literature

BACKGROUND AND PURPOSE

The papillary tumor of the pineal region (PTPR) was described as a distinct new entity for the first time in 2003 by our team and has been included in the last 2007 WHO classification of tumors of the Central Nervous System. We describe the histopathological characterization of PTPR and present a review of the literature.

METHODS

The description of the histological and immunological features of PTPR is based on the 2007 WHO classification.

RESULTS

PTPR affects both children and adults, and mostly young adults in the third decade. PTPR is a neuroepithelial tumor occurring in the vicinity of the pineal gland, and characterized by its papillary architecture. The papillae are lined by multi-layered cuboidal to columnar epithelioid tumoral cells arranged in perivascular pseudorosettes. Immunohistochemistry shows strong reactivity for cytokeratins, particularly for cytokeratin 18. On electron microscopy, PTPR reveals ultrastructural features indicative of ependymal differentiation, including abundant microvilli at the apical cell pole. The differential diagnosis includes a variety of other papillary tumors, most notably papillary ependymoma, choroid plexus papilloma, papillary meningioma, and metastatic papillary carcinoma in adults. On the basis of ultrastructural and immunohistochemical features, it has been suggested that a PTPR arises from specialized cytokeratin-positive and nestin-positive ependymal cells that are derived from the subcommissural organ. Although the precise histological grading criteria of PTPR remain to be defined, its biological behavior may correspond to WHO grade II or III.

Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study

AIMS

Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification.

METHODS

A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival.

RESULTS

The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres.

CONCLUSIONS

The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

Histological features and expression of enzymes implicated in melatonin synthesis in pineal parenchymal tumours and in cultured tumoural pineal cells

Pineal parenchymal tumours (PPT) are rare neoplasms and there have been few in vitro studies. Their capacity for synthesizing and secreting melatonin has been only partially examined. We investigated the presence of messenger RNA (mRNA) encoding tryptophan hydroxylase (TPH), arylalkylamine N-acetyltransferase (AANAT), hydroxyindol-O-methyltransferase (HIOMT), three enzymes involved in melatonin synthesis, and c-myc, a tumoural marker, in 10 PPT, one papillary tumour of the pineal region (PTPR), cell cultures derived from four PPTs and from three other tumours of the pineal region, and in normal pineal gland. Moreover, protein expression of TPH was investigated in three PPT and PTPR. Quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry were used and the melatonin production by tumoural cells in vitro was analysed by radioimmunoassay. We showed that all the tumoural tissues and cells contained c-myc mRNA. mRNAs encoding TPH, AANAT and HIOMT were detected in all PPT, suggesting that tumour cells can synthesize melatonin. Only PPT expressed TPH protein. Cultured cells lost expression of transcripts throughout passages even if ultrastructural study revealed the presence of characteristic organelles in these tumoural cells. Nevertheless, the basal secretion of melatonin observed in one PPT culture is in favour of a maintained melatonin production and secretion by tumoural pinealocytes, but melatonin production was not stimulated by a beta noradrenergic agonist. Moreover, PTPR never expressed mRNA encoding TPH, AANAT and HIOMT. Our results may contribute to a better understanding of the biology of PTT and PTPR and may help to the diagnosis of these rare tumours.

[Intracranial ependymomas in adult patients. Retrospective analysis of 121 cases from the multicentric French study]

Ependymomas are rare intracranial tumors observed in adults. Prognostic factors as well as proper therapeutic management remain controversial. We report a retrospective study of 121 cases intracranial ependymomas diagnosed between 1990 and 2004 in adult patients. Mean age was 46 years with a 1/1 sex-ratio. Supratentorial and infratentorial localization was noted for 41 (33.9%) and 80 (66.1%) patients respectively. Total gross resection was achieved for 62.8% of tumors. WHO staging was grade II for 72.7% and III for 27.3%. Recurrence developed in 41 (33.9%) patients. Median follow-up was 70 months. The 5-year and 10-year overall survivals were 85 and 76% respectively; the respective progression-free survivals were 64 and 43%. At univariate analysis, age, KPS, localization, extent of surgery and histological grade were correlated with overall survival. At multivariate analysis age, location, histological grade and extent of surgery contributed most to prediction of overall survival. Concerning progression-free survival, univariate analysis found age, KPS, localization, extent of surgery, complementary treatment and histological grade to be correlated with recurrence. Multivariate analysis retained extent of surgery, histological grade and complementary treatment as the most important predictors of progression-free survival. This study demonstrated that extent of surgery and tumor grade are the two main prognostic factors in adult intracranial ependymomas with respect to overall and progression-free survival. Furthermore, our data suggest that postoperative radiotherapy significantly increases progression-free survival in patients with incompletely resected grade II tumors.

[Cerebral amyloid angiopathy]

Cerebral amyloid angiopathy (CAA) is characterized by deposition of cerebrovascular amyloid protein in the media of leptomeningeal vessels. (amyloid B protein, cystatin C, transthyretin, gelsolin, and prion protein). It is a cause of cerebrovascular disorders including cerebral hemorrhage, cognitive impairment and unusually transient neurological symptoms. It is the main contributing factor to cerebral hemorrhage after hypertension in the elderly. We aimed to review epidemiological, pathophysiological and clinical and MRI imaging data in CAA.

Phase II study of the combination of cisplatin + temozolomide in malignant glial tumours in children and adolescents at diagnosis or in relapse (cistem2/nct00147160)

9543

Background: Temozolomide has been shown moderately effective in pediatric high-grade glioma (HGG). By decreasing the activity of MGMT, principal mechanism of resistance to temozolomide, cisplatin may increase the activity of this alkylating agent. Methods: Patients aged 4 to 21y with HGG outside the brainstem were treated at diagnosis or at relapse every 28 days with a combination of cisplatin 80 mg/m2 intravenously on day-1 and temozolomide 200 mg/m2 orally on days 2–6, according to the pediatric phase I recommendations. Patients treated at diagnosis had to proceed to involved field radiotherapy after the chemotherapy window. According to initial response, patients were offered additional courses, up to seven. We considered that this combination would be of interest if the response rate was superior or equal to 20%, using a two-stage Simon design in 3 cohorts: evaluable non measurable (infiltrative) at diagnosis (cohort A1); measurable disease (nodular) at diagnosis (A2); recurrent disease (B). The primary endpoint was complete or partial response after two courses, confirmed by central review. Up to 29 evaluable pts were to be entered in each cohort. If fewer than 4/29 responses were observed, it would be concluded that the combination is ineffective. Results: 56 pts were entered from 10/2003 through 07/2006 in 25 centers. One was excluded after central pathology review and 3 due to insufficient radiology work-out. 42 had grade III and 13 grade IV gliomas, including 21 tumors with oligodendroglial features. No response was observed in the first 11 pts in cohort A1 and in the first 12 pts in cohort B. Two partial and 4 minor responses were confirmed in 29 pts of cohort A2 leading to a 7% response rate (95% CI, 1–23%). Median time to progression was 1.7, 7.1 and 6.9 months in cohorts A1, A2 and B, respectively. Toxicity was manageable except in pts with large infiltrative lesions who did not tolerate hydration. Conclusion: CISTEM combination has insufficient efficacy in pediatric compared to adult HGG despite efficient down-regulation of MGMT activity. To overcome resistance to temozolomide in children and adolescents, one may need to target other known resistance mechanisms such as mismatch-repair deficiency.

[Table: see text]

Reactive perivascular T-cell infiltrate predicts survival in primary central nervous system B-cell lymphomas

Well-established histopathological prognostic factors are lacking in primary central nervous system (CNS) lymphomas (PCNSL). The present study investigated the presence and prognostic role of tumour necrosis (TN) and reactive perivascular T-cell infiltrate (RPVI), defined as a rim of small reactive T-lymphocytes occurring alone or located between the vascular wall and large neoplastic cells, in tumour samples from 100 immunocompetent patients with PCNSL. World Health Organization histotypes of the patients were: 96 diffuse large B-cell lymphomas, two Burkitt-like lymphomas, one anaplastic large T-cell lymphoma and one unclassified B-cell lymphoma. TN was observed in 24 (24%) cases and RPVI in 26 (36%) of 73 assessable cases. Patients with RPVI-positive lesions exhibited a significantly better overall survival (OS) than patients with RPVI-negative lymphoma, particularly among patients treated with high-dose methotrexate-based chemotherapy (3-year OS: 59 +/- 14% vs. 42 +/- 9%, P = 0.02). By contrast, the presence of TN did not demonstrate prognostic significance. Multivariate analysis confirmed an independent association between RPVI and survival. In conclusion, the presence of RPVI is independently associated with survival in PCNSL. This parameter can be easily and routinely assessed at diagnosis on histopathological specimens.

Épendymomes intracrâniens de l'adulte. Diagnostic histologique et facteurs histopronostiques

BACKGROUND

Intracranial ependymomas are rare in adults and histopathological prognostic factors are poorly determined.

PURPOSE

A retrospective multicentric study was conducted in France in order to assess the prognostic value of histology.

MATERIAL

Between 1990 and 2004, 216 adult patients with newly diagnosed ependymomas were treated in 19 French centers. Eligibility required institutional histopathological confirmation of an ependymoma and available clinical history and MRI features (see comparison paper).

METHODS

Histological preparations and one paraffin embedded block from each patient were sent to Pr D. Figarella-Branger in Marseille. Central review by four neuropathologists (D. Figarella-Branger, A. Maues de Paula, C. Fernandez and A. Jouvet) was performed. Specimens for which all pathologists agreed with the histological diagnosis of ependymomas were included, whereas cases for which all disagree were excluded and reclassified. In the event of doubt and/or discrepancies between pathologists immunostaining was performed in order to reach a consensus diagnosis. Diagnostic of ependymomas was confirmed in 121 cases (56%). In theses cases, ependymomas were classified according to the WHO system (subtype and grade). The potential prognostic value (overall survival OS and disease free survival DFS) of the following histological parameters was examined: perivascular pseudorosettes, ependymal rosettes, hyalinized vessels, mitotic index, microvascular proliferation, necrosis, area of increased cellularity, nuclear atypia, brain invasion and Mib-1 labelling index.

RESULTS

Among the 121 ependymomas, 88 were grade II (47 classic, 17 cellular, 2 papillar, 6 clear cells and 16 tanicytic) and 33 grade III. WHO grading, occurrence of microvascular proliferation, necrosis, nuclear atypia and high proliferative index were correlated with both OS and DFS. Moreover, quantification of certain parameters enabled a reproducible grading system correlated with both OS and DFS.

IRM de diffusion-perfusion dans l’évaluation des lymphomes cérébraux

Because of the increasing incidence of cerebral lymphoma, it is critical for patient management to recognize the MR features of this disease. We present the characteristic morphological and functional MRI features of this tumor. The findings on MRI studies, including morphological, diffusion and perfusion imaging, performed in 9 biopsy-proven cases of cerebral lymphoma with 13 lesions are presented and analyzed, and are discussed in comparison with published literature data. All patients underwent diffusion-weighted imaging with a single shot echo-planar pulse sequence. Dynamic susceptibility-contrast MRI was performed using a T2*-weighted gradient-echo echo-planar sequence after intravenous injection of chelates of gadolinium at the rate of 6 ml/s and a temporal resolution of 1 second. All cases of cerebral lymphoma appeared hypointense or isointense on T1-weighted images and in 75% of cases iso- or hypointense on T2-weighted images. All lesions enhanced except one in a patient receiving steroid therapy. On diffusion-weighted images, tumours were hyperintense with normal or decreased ADC values (0.717+/-0.152.10-3 mm2/sec, range: 0.550-1.014) and an ADC ratio tumour/normal white matter of 0.974+/-0.190 (range: 0.768-1.410). On perfusion, the signal intensity-time curve of each tumour showed a characteristic type of curve with a significant increase of the signal intensity above the baseline and a low maximum relative cerebral blood volume ratio (rCVBmax) of 1.43+/-0.64 (0.55-2.62). Due to their higher cellularity, the lack of neoangiogenesis, and the increased permeability of the blood-brain barrier related to the infiltration of blood vessels wall by lymphomatous cells, cerebral lymphoma presents characteristic diffusion and perfusion MRI features that should be useful for diagnosis and patient follow-up.

Immunohistochemical profile and chromosomal imbalances in papillary tumours of the pineal region

The histopathology of papillary tumours of the pineal region (PTPR) closely resembles that of ependymomas and choroid plexus tumours. Therefore, immunohistochemical staining profiles were investigated in a series of 15 PTPR. In addition to cytokeratin, synaptophysin and glial fibrillary acidic protein expression, PTPR were examined for the presence of dot- or ring-like epithelial membrane antigen (EMA) immunoreactivity typically encountered in ependymoma, staining for inwardly rectifying potassium channel Kir7.1 and stanniocalcin-1 (specifically expressed in choroid plexus tumours) as well as microtubule-associated protein-2 (MAP-2). Furthermore, comparative genomic hybridization was performed in five PTPR. Cytokeratin was expressed in all PTPR examined, whereas glial fibrillary acidic protein and synaptophysin staining were absent. Dot- or ring-like EMA immunoreactivity was only observed in 1 out of 15 PTPR. Membranous Kir7.1 and cytoplasmic stanniocalcin-1 staining were present in the minority of PTPR (3/15 and 4/15, respectively). In contrast, MAP-2 immunoreactivity was encountered in 13 out of 15 PTPR, but was significantly less frequently observed in a series of choroid plexus tumours (7/37). PTPR mainly presented with chromosomal losses affecting chromosomes 10 (4/5 cases) and 22q (3/5 cases) as well as gains on chromosomes 4 (4/5 cases), 8 (3/5 cases), 9 (3/5 cases) and 12 (3/5 cases). To conclude, the majority of PTPR can be distinguished from ependymomas and choroid plexus tumours by absent staining for epithelial membrane antigen, Kir7.1 and staniocalcin-1 as well as the presence of distinct MAP-2 immunoreactivity. Antibodies directed against these antigens are thus expected to be valuable markers in the diagnosis of papillary tumours located in the vicinity of the third ventricle.

Pineal parenchymal tumors: a correlation of histological features with prognosis in 66 cases

The WHO classification of CNS tumors divides pineal parenchymal tumors (PPT) into pineocytoma (PC), pineoblastoma (PB) and mixed pineocytoma-pineoblastoma or PPT with intermediate differentiation. The reported incidence of mixed/intermediate PPT varies and this may reflect the difficulty in classifying tumors of this type. In an attempt to overcome the problem of the classification of PPT with intermediate differentiation, we describe the relationship between histological features and patient survival in a large cooperative series of 66 PPT from 12 neurosurgical centres. All tumors were studied with both light microscopy and immunohistochemically using antibodies against glial markers or neural/neuroendocrine markers. Our series included 11 PC, 39 mixed/intermediate PPT and 16 PB. A number of mitoses greater than 6 and the presence of necrosis were associated with a poorer outcome, while positive immunostaining for neurofilaments was associated with a better survival. We propose a new prognostic grading of 4 grades, grade I for PC, grade II for PPT with fewer than 6 mitoses and positive immunolabelling for neurofilaments, grade III for PPT with either 6 or more than 6 mitoses or fewer than 6 mitoses but without immunostaining for neurofilaments and grade IV for PB.

[Criteria of diagnosis and grading of oligodendrogliomas or oligo-astrocytomas according to the WHO and Sainte-Anne classifications]

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]

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.

[11C]-Methionine PET: dysembryoplastic neuroepithelial tumours compared with other epileptogenic brain neoplasms

BACKGROUND AND OBJECTIVES

Brain tumours responsible for longstanding partial epilepsy are characterised by a high prevalence of dysembryoplastic neuroepithelial tumour (DNT), whose natural evolution is much more benign than that of gliomas. The preoperative diagnosis of DNT, which is not yet feasible on the basis of available clinical and imaging data, would help optimise the therapeutic strategy for this type of tumour. This study tested whether [(11)C]-methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumours.

METHODS

Prospective study of 27 patients with partial epilepsy of at least six months duration related to a non-rapidly progressing brain tumour on magnetic resonance imaging (MRI). A structured visual analysis, which distinguished between normal, moderately abnormal, or markedly abnormal tumour methionine uptake, as well as various regions of interest and semiquantitative measurements were conducted.

RESULTS

Pathological results showed 11 DNTs (41%), 5 gangliogliomas (18%), and 11 gliomas (41%). MET-PET visual findings significantly differed between the various tumour types (p<0.0002), regardless of gadolinium enhancement on MRI, and were confirmed by semiquantitative analysis (p<0.001 for all calculated ratios). All gliomas and gangliogliomas were associated with moderately or markedly increased tumour methionine uptake, whereas 7/11 DNTs had a normal methionine uptake, including all six located in the mesiotemporal structures. No DNT presented with a marked MET-PET abnormality.

CONCLUSION

Normal MET-PET findings in patient with an epileptogenic and non-rapidly progressing brain tumour are suggestive of DNT, whereas a markedly increased tumour methionine uptake makes this diagnosis unlikely.

[Results of the Sainte-Anne - Lyons series of 318 oligodendroglioma in adults]

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.

Les oligodendrogliomes supratentoriels de l’enfant

BACKGROUND AND PURPOSE

The goal of this study was to analyze the main aspects of oligodendrogliomas observed in children.

METHOD

The records of 35 children aged 15 years or younger (23 from Marseilles and 12 from Lyons) were reviewed. Clinical signs and symptoms, imaging findings (CT scan and pre- and post-operative MRI), extent of surgical resection, histology according to the WHO and Ste-Anne grading and survival were analysed. Considering all these factors, a statistical analyzis was undertaken in order to identify prognostic factors.

DISCUSSION AND CONCLUSION

Oligodendrogliomas are rare tumors in children. The most important differential diagnosis to discuss is dysembryoplastic neuroepithelial tumor. Our study allowed us to distinguish several subgroups of patients with a different prognosis: thalamic tumors with a dismal prognosis versus hemispheric tumors. A group of cortical tumors we called "DNT-like" (hemispheric cortical tumor, isolated epilepsy, without neurological deficit and reased ICP, without edema and mass effect on MRI) with an excellent prognosis like the group with epilepsy. Histological grading (grade A/grade B and grade II/grade III) is also a prognostic factor.

[Delayed post-anoxic leukoencephalopathy]

INTRODUCTION

The onset of post-anoxic encephalopathies can be delayed after the acute hypoxic injury.

CASE REPORT

We present the case of a 45-year-old woman who achieved complete recovery from an episode of hypoxia related to a suicide attempt (ingestion of benzodiazepine). Three weeks later she developed a confusional state with akinetic mutism and parkinsonism. Brain CT-scan showed bilateral hemispheric white matter hypodensities. MRI showed extensive bilateral hyperintensities on T2-weighted and Flair sequences within the hemispheric white matter and the globus pallidus. EEG showed diffuse slow activity. All investigations for leukodystrophies were negative. Brain biopsy showed normal cortex and widespread demyelination with axonal sparing in the underlying white matter. The patient experienced a partial clinical recovery.

CONCLUSION

The clinical course and the results of paraclinic investigations were consistent with the diagnosis of delayed post-anoxic leukoencephalopathy.

High and low grade oligodendrogliomas (ODG): correlation of amino-acid and glucose uptakes using PET and histological classifications

Classification and treatment strategy of oligodendrogliomas (ODG) remain controversial. Imaging relies essentially on contrast enhancement using CT or MRI. The aim of our study was to use positron emission tomography (PET) using [18F]-flurodeoxyglucose (FDG) and [11C]-L-methyl-methionine (MET) to evaluate metabolic characteristics of ODG. We studied 19 patients with proven ODG, comparing standardized uptake values (SUV) and maximal tumor/contralateral normal tissues ratios (T/N). Imaging findings were compared with WHO, Smith and Daumas-Duport classifications. Uptake of FDG was decreased only in 8 patients, independently of grading, while MET uptake was always increased. MET uptake was significantly higher for high grade tumors grouped according to Smith or Daumas-Duport classifications, while no significant difference in MET uptake was found when using WHO classification. A different correlation was found between FDG and MET uptakes in normal tissues and high grade tumors. A trend for improved progression free survival was found for tumors that lacked contrast enhancement on MRI or those showing low FDG or MET uptake. In conclusion, MET appeared more sensitive than FDG to detect proliferation in ODG. The preferential protein metabolism, already noticeable for low-grade tumor, correlated with glucose metabolism and helped to separate, in vivo, high and low grade tumors.

Conformal irradiation for pure and mixed oligodendroglioma: the experience of Centre Leon Berard Lyon

PURPOSE

To assess whether conformal radiotherapy (CRT) after incomplete surgery or biopsy for pure oligodendrogliomas and mixed gliomas results in decreased long-term sequelae without impairing local control and while reducing irradiated volume.

MATERIALS AND METHODS

Twenty-six consecutive patients who presented with pure (21) or mixed (5) oligodendrogliomas and who were given incomplete resections were treated according 3 different strategies: CRT alone (12), chemotherapy followed by CRT (4), and chemotherapy and delayed CRT at the time of tumor progression (10). CRT consisted of multiple noncoplanar fields. Median dose was 60 Gy. Quality of CRT was assessed using tumor and normal tissue conformal indexes. The location of recurrences was assessed with MRI and dosimetric data. Late sequelae were assessed by a questionnaire exploring professional outcome, and also by a Mini Mental State Examination test.

RESULTS

The mean overall survival was 5.2 years. Fifteen patients experienced a local relapse. All but 1 occurred in the 95% isodose. Among 11 nonevolutive patients, 6 have a full-time or part-time job.

CONCLUSIONS

Despite CRT, infield recurrence was a common feature in patients with oligodendrogliomas and mixed tumors. Further research, including molecular biology typing of tumors and type of treatment, is warranted to improve survival and quality of life.

[Cerebral amyloid angiopathy revealed by transient ischemic events: contribution of MRI to diagnosis and pathophysiology study]

We report the case of a 72-year-old left-handed woman presenting with episodes of paresthesias of the left arm and dysarthria consistent with transient ischemic attacks. The diffusion MRI showed hypersignals of the right corona radiata suggesting recent ischemic process whereas gradient-echo MRI revealed multiple small hypointense regions consistent with petechial hemorrhages restricted to the corticosubcortical regions. Gadolinium-enhanced, T1-weighted MRI showed focal meningeal enhancement. The diagnosis of cerebral amyloid angiopathy was supported by leptomeningeal biopsy. The association of ischemic suffering, petechial haemorrhage and meningeal enhancement as demonstrated by multisequence MRI highly suggest a cerebral amyloid angiopathy.

Differential somatostatin receptor subtype expression in human normal pineal gland and pineal parenchymal tumors

Somatostatin is a potent antiproliferative signal in both tumoral and normal mammalian cells, and altered somatostatin receptor (sst) expression is associated with carcinogenesis in human tissues. In this study, two normal and three tumoral human pineal glands were analyzed using the reverse transcriptase-polymerase chain reaction (RT-PCR) for the presence of mRNA coding for the five different somatostatin receptors (sst1-sst5). Pineal parenchymal tumor (PPT) differentiation was confirmed by immunohistochemical detection of neuroendocrine markers (synaptophysin, neurofilaments, and chromogranin A). The presence of mRNA coding for c-myc, a proto-oncogene, and for tryptophan hydroxylase (TPOH), serotonin N-acetyltransferase (NAT), and hydroxyindole-O-methyltransferase (HIOMT), enzymes of the melatonin pathway, was also analyzed by RT-PCR. Only the tumoral tissues contained c-myc mRNA. All five tissues contained TPOH, NAT, and HIOMT mRNA, the levels of HIOMT mRNA being lower in PPT than in the normal pineal gland, suggesting that PPT retain the ability to synthesize melatonin. All tissues contained sst1, sst2, and sst3 transcripts, but not sst4, while small amounts of sst5 mRNA were only found in normal pineal glands. Real-time PCR, performed only with the most abundant subtpe sst2, evidenced an about sixfold higher level in in normal pineal glands. These results demonstrate the presence of somatostatin receptors in the human pineal gland, as described in other species, and point to a differential expression of the sst2 and sst5 subtypes associated with carcinogenesis.

Temozolomide in malignant gliomas of childhood: a United Kingdom Children's Cancer Study Group and French Society for Pediatric Oncology Intergroup Study

PURPOSE

To determine the response rate of the malignant gliomas of childhood to an oral, daily schedule of temozolomide.

PATIENTS AND METHODS

A multicenter, phase II evaluation of an oral, daily schedule of temozolomide (200 mg/m(2) on 5 consecutive days) was undertaken in children with relapsed or progressive, biopsy-proven, high-grade glioma (arm A) and progressive, diffuse, intrinsic brainstem glioma (arm B). Evidence of activity was defined by radiologic evidence of a sustained reduction in tumor size on serial magnetic resonance imaging scans.

RESULTS

Fifty-five patients were recruited (34 to arm A and 21 to arm B) and received 215 cycles of chemotherapy. Grade 3/4 thrombocytopenia was the most frequent toxic event (7% of cycles). Prolonged myelosuppression resulted in significant treatment delays and dose reductions (17% and 22% of cycles, respectively). Two toxic deaths were documented and were related to myelosuppression and sepsis in one patient and pneumonia in a second. The overall (best) response rate was 12% for arm A (95% confidence interval [CI], 3 to 28 in the study cohort, and 2 to 31 for eligible patients) and 5% and 6%, respectively, for arm B (95% CI, 0 to 26 in the study cohort, and 0 to 27 for eligible patients). Stabilization of disease was also documented and was most noteworthy for brainstem gliomas, where two patients achieved both radiologic static disease and discontinued steroid medication.

CONCLUSION

Despite moderate toxicity, objective response rates to temozolomide have been low, indicating that temozolomide has minimal activity in the high-grade gliomas of childhood.

Intracranial ependymomas in adult patients: analyses of prognostic factors

OBJECTIVE

The goal of our study is to identify significant prognostic factors for a series of intracranial ependymomas in an adult population. Age, location, histology, preoperative clinical status, extent of resection and radiotherapy were examined.

METHODS

Our series includes 34 patients. Ten tumors were located in the brain parenchyma, 5 in the lateral ventricle, 8 in the third and 11 in the fourth ventricle. Seventeen ependymomas were grades 2 and 17 were anaplastic. Surgical resection was gross-total in 27 patients and partial in 7.

RESULTS

At a mean follow-up of 9 years (+/- 1 year) 16 patients died and, among the 18 survivors 14 are in complete remission and 4 present a local recurrence. The 5- and 10-year overall survival rates were respectively 62% and 43%. The 5- and 10-year progression-free survivals were 47% and 43%. Univariate analysis revealed that location in the brain parenchyma and anaplasia are the only statistically significant predictors of poor outcome.

CONCLUSION

We can make out three groups of patients from our series: the first encompasses patients operated on for an intraparenchymal tumor, in all our cases an anaplastic ependymoma, with a 5-year rate of tumor-related deaths of 100%. The second group includes fourth ventricle ependymomas, which are mostly grade 2 tumors. They display a 10-year survival rate of 90%. Last group entails lateral and third ventricle ependymomas, of both low and high grade, with a 10-year survival rate of 60% for lateral ventricle and 35% for third ventricle tumors.