PubMed Health⌕ Search

Biomedical subjects

G Saint-Pierre

Publications and source records attributed to G Saint-Pierre.

18 recordsLinked to original sources
PubMed2005

[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.

Astrocytoma↗
PubMed2003

[Calcified brain metastases of a pulmonary neuroendocine carcinoma].

We describe an unusual case of pulmonary neuroendocrine carcinoma of intermediate cell type, revealed by calcified metastatic nodules of the brain in a 49-year-old man. Histological examination of the brain lesions disclosed necrosis and calcification in the center with small and medium-sized carcinoma cells. Pathophysiological mechanisms of such calcifications in metastasis lesions are reviewed.

Brain Diseases↗
PubMed2002

Myelopathy and sciatica induced by an extradural S1 root haemangioblastoma.

Haemangioblastomas are vascular tumours which mainly involve the central nervous system and retina, often in the setting of von Hippel-Lindau disease. Haemangioblastomas occurring outside the central nervous system are uncommon. Wherever it is, recognising this tumour prior to surgery is desirable, as preoperative embolisation may be considered. We report the clinical, imaging and pathological features of a sporadic sacral root haemangioblastoma in a 58-year-old man with chronic sciatica and myelopathy. The diagnosis was questioned preoperatively because an enlarged sacral foramen, seen to be filled by a highly vascular, enhancing mass and dilated vessels. Myelopathy was attributed to the presumed high venous pressure resulting from increased flow in veins draining the vascular tumour. Microneurosurgical excision was performed after endovascular embolisation and led to persistent clinical improvement.

Cerebellar Neoplasms↗
PubMed2001

Central nervous system cavernomas in the pediatric age group.

Pediatric CNS cavernomas still are diagnostically and therapeutically challenging lesions. With the help of magnetic resonance imaging, the natural history of cavernomas now guiding therapeutic strategies is well documented in adults but remains poorly known in the pediatric age group, since most previous studies dealt with adult and pediatric patients together. This paper focuses on clinical, imaging, and therapeutic features and differential diagnosis of CNS cavernomas with an emphasis on their specificities in the pediatric age group. It is based upon a critical review of the literature and our single-center experience with 36 children (35 with cerebral cavernomas and one with spinal cord cavernoma) operated on during the period of 1985-1999 as well as with seven additional unoperated pediatric cases. Our experience resembles that of other authors regarding the high hemorrhagic risk in children compared to adults. These angiographically occult vascular malformations are often revealed by the sudden onset of intracerebral hematoma with acute focal neurologic deficits, concomitant manifestations, and/or signs of raised intracranial pressure. True epilepsy is less common and may be related to chronic or recurrent microbleeding. Evocative imaging findings are also somewhat different in the two age groups, and we propose here an imaging classification of cerebral cavernomas based on both morphological and signal characteristics that is applicable to the pediatric age group. A sharply demarcated spherical intracerebral hematoma or heterogeneous lesion should always make one consider the hypothesis of a cavernoma. For symptomatic lesions and most rapidly growing asymptomatic lesions, the treatment of choice is complete microsurgical excision preceded by careful anatomical and functional evaluation. Improvements in surgical techniques and anesthesiology over recent years have brought good results in most operated children. The limited role of radiosurgery in the management of pediatric cerebral cavernomas is discussed. There is still a need for well-conducted specific evaluation of the natural history of these lesions in the pediatric age group to aid in systematic research, follow-up, and therapeutic strategies for asymptomatic cavernomas.

Central Nervous System Neoplasms↗
PubMed2001

[Multiple intracranial and intraspinal meningiomas successively discovered in the absence of neurofibromatosis: 2 cases].

Multiple meningiomas in different neuroaxial compartments are quite rare. We describe the case of a 44-year-old woman who developed three intracranial meningiomas and 8 years later a T3 dorsal meningioma. Histologically, the frontal and dorsal tumors appeared as benign psammomatouss meningiomas. Both tumors were removed successfully. The second patient was a 31-year-old woman who developed right benign fronto-parietal transitional meningioma. She presented local and spheno-orbital recurrences, then a lombo-sacral lesion. The histological picture worsened from benign to malignant with multiple recurrences. Several mechanisms could account for multiple meningiomas. Such meningiomas could arise from a single primary tumor via subarachnoidal spread of a benign or malignant nature. Alternatively, they could be atypical forms of neurofibromatosis type 2 or tumors with a multifocal origin.

Adult↗
PubMed2000

Parenchymal pineal tumors: a clinicopathological study of 76 cases.

PURPOSE: The aim of this study was to identify factors that could lead to optimization of the management of pineal parenchymal tumors (PPT) which remains equivocal and controversial. METHODS AND MATERIALS: In order to determine factors that influence PPT prognosis, a series of 76 consecutive patients from 12 European centers with histologically proven tumors was retrospectively reviewed. The clinical records and material for histologic review were available in all cases. Follow-up was achieved in 90% of cases. RESULTS: According to WHO classification, there were 19 pineocytomas, 28 intermediate and mixed PPT, and 29 pineoblastomas. According to a four-grade institutional classification, there were 11 Grade 1, 27 Grade 2, 20 Grade 3, and 18 Grade 4. Surgical resection was attempted in 44 patients, whereas 30 had biopsy only. In one case, diagnosis was made at autopsy and in another on spinal deposits. Forty-four patients were irradiated following surgery, 15 patients received chemotherapy. Forty-one patients were alive (median follow-up: 85 months); 9 patients died perioperatively; 26 patients relapsed. Univariate analysis showed a good outcome correlated with age above 20 years, tumor diameter less than 25 mm, and low-grade histology. Multivariate analysis confirmed histology and tumor volume to be significant independent prognostic factors. The extent of surgery and radiotherapy had no clear influence on survival. CONCLUSIONS: This review highlights the prognostic features of PPT and may help to determine treatment strategies based on radiologic and pathologic characteristics.

Adolescent↗
PubMed2000

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.

Adolescent↗
PubMed2000

[Central nervous system neurocytomas: clinicopathological analysis of tree cases].

Central nervous system neurocytoma is a rare benign tumor of neuronal origin. Because of some clinical and radiological findings CNS neurocytomas were confused with other intraventricular lesions (ependymomas, choroid plexus papilloma, oligodendrogliomas, subependymal astrocytomas). Pathological diagnosis improved with immunohistochemical and electron microscopic studies. We present three cases of intraventricular neurocytomas confirmed by immunohistochemical studies. According to the literature clinical signs, radiological features, surgical and pathological findings are discussed.

Adolescent↗
PubMed2000

[Practical recommendations for management of the biopsy in an expansive intra-cerebral process].

Diagnosis of an intracerebral mass requires a good collaboration between clinicians and pathologists. Different techniques may be necessary. The interest of cytological preparations and immunohistochemistry is reported. The main characteristic features of cerebral tumors are described and the differential diagnosis with reactive and inflammatory masses simulating neoplasia is discussed.

Biopsy↗
PubMed1999

[Thoracic spinal cord compression by a gouty tophus. Case report. Review of the literature].

An unusual case of thoracic spinal cord compression caused by extradural tophaceous deposits is reported in a 59-year-old female with a long-standing history of gout involving the metatarsophalangeal joints. T1 and T2 magnetic resonance images of the spine illustrated an extradural hyperintense signal extending from T2 to T9. A decompressive laminectomy disclosed a white caseum-like material in the extradural space, together with a small organized hematoma. Histologic examination showed areas of amorphous substance containing urate crystals surrounded by inflammatory cells, which was diagnosed as a gouty tophus. The patient made an uneventful recovery after surgery. Fifteen similar cases of the literature are reviewed. Although spinal involvement by gout seems relatively common, a compression of the spinal cord or of the cauda equina in gout patients seems exceptional. The diagnosis should be considered in patients showing a relevant history of gout, but spinal cord compromise may also represent the initial manifestation of the disease.

Arthritis, Gouty↗
PubMed1997

[Intramedullary subependymoma of the cervical spinal cord. Review of the literature a propos of a case].

A case of intramedullary subependymoma (SE) of the cervical spinal cord is reported. A 35 year-old female patient developed paresthesiae in her right upper and lower limbs for approximately two years. Magnetic resonance imaging (MRI) of the cervical spinal cord disclosed an intrisic medullary tumor at the C2-C3 levels, predominantly involving the right hemicord. At surgery, a subpial ependymoma was totally removed using the ultrasonic surgical aspirator with no resulting anomalies of the intraoperative somatosensory evoked responses. The patient made a good recovery. At one-year follow-up, she had resumed her previous occupation and complained only from minor sequelae. Twenty-nine spinal cord SE of the literature are detailed. It is likely that they account for less than two per cent of all spinal cord tumors. A majority of cases involved the cervical cord or the cervicothoracic junction. Signs and symptoms are similar to those of other spinal intramedullary tumors. In 17 cases explored by MRI, no specific pattern could distinguish SE from astrocytomas or ependymomas, except perhaps for a more marked tendency for SE to grow excentrically within the cord or to show an exophytic component. Spinal cord SE show pathological features grossly comparable to those described in intracranial SE with clusters of small glial cells scattered among densely packed fibers. Histogenesis of SE has been a matter of debate over years, whereas it is currently admitted that they may represent a variant of ependymomas. In conclusion, most clinical and imaging features of spinal cord SE are similar to those of other pathological varieties. Radical removal is the most appropriate treatment modality, despite inherent risk of postoperative deterioration and significant sequelae on long term follow-up.

Adult↗
PubMed1995

Giant hypothalamic hamartoma: an unusual neonatal tumor.

A case of neonatal manifestation of giant hypothalamic hamartoma is reported. It is suggested that hypothalamic hamartoma should be included in the list of neonatal intracerebral tumors. Magnetic resonance imaging appearance similar to that of normal gray matter on T1-weighted images and slightly hyperintense on T2-weighted images, without enhancement after gadolinium injection, is suggestive of the diagnosis. Hypothalamic hamartomas are congenital malformations, consisting of disorganized mature neuronal elements in proportions similar to that of normal tissue [1]. They are clinically evidenced in infants ranging from 1 to 7 years of age [1-5]. This report describes a histologically proved giant hypothalamic hamartoma diagnosed in the neonatal period. Magnetic resonance imaging (MRI) is helpful to distinguish this congenital non-evolutive malformation from more aggressive neonatal tumors.

Female↗
PubMed1994

Structural and ultrastructural characteristics of human pineal gland, and pineal parenchymal tumors.

We have studied 20 pineal parenchymal tumors (PPT) and 4 normal or cystic pineal glands both by light and electron microscopy and immunohistochemistry with antibodies against glial markers [glial fibrillary acidic protein (GFAP) and protein S-100] or neural/neuroendocrine markers [neurofilaments (NF), synaptophysin and chromogranin A]. Light microscopy revealed the cellular organization of pinealocytes in the normal gland and in different morphological types of pineal tumors (typical pineocytomas, PPT with intermediate differentiation, mixed PPT exhibiting elements of both pineocytoma and pineoblastoma and pineoblastomas). Immunohistochemistry showed the presence of GFAP and protein S-100 in interstitial cells in non-neoplastic pineal gland. Cell processes were labeled with anti-synaptophysin and anti-NF antibodies. No immunoreactivity was found for chromogranin A in non-neoplastic pineal gland. In pineocytomas, GFAP and protein S-100 were observed in interstitial cells. Synaptophysin and NF were present in the large rosettes of pineocytomas. Synaptophysin, NF and chromogranin A were present in pineocytomas with a lobular arrangement of cells. Anti-chromogranin A immunoreactivity was also seen in lobular areas of some PPT with intermediate differentiation. Analysis of normal human pineal gland by electron microscopy showed the presence of vesicle-crowned rodlets (VCR or synaptic ribbons), fibrous filaments (F), paired twisted filaments but few dense-core vesicles (DCV) in normal pinealocytes. Tumoral pineal cells appeared to differentiate either towards a neurosensory pathway characterized by the presence of sensory cells elements (VCR and F), or towards a neuroendocrine pathway, with the occurrence of many DCV. Immunogold labeling demonstrated the presence of chromogranin A in neurosecretory granules.

Adolescent↗
PubMed1993

[Alexander's disease in adults and diffuse cerebral gliomatosis in 2 members of the same family].

A 31-year old woman died after 10 years of progressive dysautonomia and cerebellar and pyramidal symptoms. CT scan showed pontine, bulbar and cerebellar atrophy. Post-mortem examination revealed Rosenthal's fibers widespread throughout the CNS, but especially in the subependymal and perivascular regions. White matter cavitations involving peri-ventricular regions, hilum of dentate nuclei and pons were observed, leading to a diagnosis of adult form of Alexander's disease. At the age of 5, the patient had been operated upon for a chiasmatic tumor. Microscopic examination revealed a pilocytic astrocytoma without Rosenthal's fibers. No complementary radiotherapy had been done. Her mother has been operated upon in 1972, for a high-grade glioma and is still alive 20 years later. This suggests diffuse cerebral gliomatosis. This family history may suggest a relation between these different diseases. They might be the result of a transmissible astrocytic abnormality with varying expression.

Adult↗
PubMed1993

Brain banking for immunocytochemistry and autoradiography.

The aim of a human brain bank is to establish groups of matched brains (normal control versus pathological groups) for studying human diseases of the nervous system. This bank is obtained by means of autopsy performed with a very short post-mortem delay and from clinically and neuropathologically well-documented patients. According to research protocols, two types of brain tissue storage are performed: fixed tissue or frozen tissue. Brain dissection procedures are performed according to precise anatomical boundaries of each brain region. This paper will center on the questions raised by brain banking in relation to histological and immunocytochemical studies and to biochemistry and autoradiography of binding sites. The lack of neuroanatomical data of the human brain leads us to compare anatomical results obtained in animals to that of the human. Moreover, it is clear that human brains present numerous interindividual differences (Kopp et al., 1977; Jack et al., 1989). Therefore, investigations of the human brain should be made on a large series of brains indicating the necessity of a well-documented brain bank of tissue from normal controls and patients.

Autoradiography↗
PubMed1992

[Abnormalities of the nervous system in sudden infant death syndrome].

Anomalies seem to be present in the brain of infants who died of sudden infant death syndrome. They imply dendritic synapses, myelinisation, some neurotransmitters, some peptides, their enzymes and receptors. More precisely, catecholaminergic systems seem to be abnormal. The changes were found mainly in brain stem, in vegetative central areas. These anomalies are probably maturational in nature. They could represent a fragility of vegetative control systems, especially cardiorespiratory and swallowing control systems. They probably do not explain, per se, the occurrence of death; they probably would need to be potentiated by additional etiological factors (environmental, viral, etc). These anomalies have to be considered as provisional and, in our opinion, need confirmation. Apart from the brain stem, other areas are under investigation, particularly cerebral structures implied in temperature control, sleep-wakefulness control and hemispheric structures.

Brain↗
PubMed1985

[Lambl's excrescences].

First described in 1856 as small, filiform, pale outgrowths from the free border of the cardiac valves, larger specimens can now be detected by echocardiography. We analysed 30 consecutive cases to define the anatomic of LE were determined macroscopically and histological examination was then carried out with six different stains. LE was found on 18 aortic, 10 mitral, 2 tricuspid and 2 pulmonary valves in the 30 patients examined. Their size ranged from 2 to 12 mm with 7 examples being over 5 mm long. Histologically there appeared to be two forms: mobile, pediculated lesions (20 cases) either with the usual changes of an acellular fibrous axis containing rings of granulous orcenophilic material or with more complex associations of these changes resulting in pseudo-papillomata of the valves; the second form of LE is incorporated in the valve itself. It thickens the valve and becomes covered by a layer of flattened endothelium. The histological study suggested several pathogenic mechanisms, all related to local conditions rather than to general circulatory changes: folding of the valvular endothelium onto itself followed by organisation into tubular structures filled with oedema and hyaklin, deposits of fibrin layers on zones of endothelial ulceration caused by trauma on the line of apposition of the cusps with partial detachment of fibrinous material which then endothelialises; finally, subendocardial incorporation of oedema, fibrin, and red blood cells. Although LE may occur in association with non-bacterial thrombolic endocarditis, these two conditions do not seem to be related.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗