Philippe Bret

CHU de Lyon - Hôpital Neurologique et Neurochirurgical Pierre Wertheimer, Lyons, Rhône-Alpes, France

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Publications (8)38.84 Total impact

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    ABSTRACT: Immediate and delayed cerebellar dysfunction may be expected after surgical resection of a medulloblastoma. We investigated whether pre-operative and delayed post-operative MRI may correlate with such sequelae. The data of 31 patients in continuous complete remission after removal of medulloblastoma, irradiation and chemotherapy, were retrospectively reviewed. Magnetic Resonance Imaging (MRI) was analyzed for the following items: preoperative MRI (ratio of the surface of the tumor/posterior fossa, presence of ventricular dilatation or tonsilar hernia, involvement of the dentate nucleus) and delayed post-operative MRI (amount of cerebellar parenchyma removed, degree of cerebellar atrophy, presence of T1 hypointense regions in remaining cerebellar area and removal of region containing dentate nucleus). These data were correlated with immediate and long-term cerebellar syndrome and daily life repercussions. On preoperative MRI, the ratio of the surface of the tumor/posterior fossa and the presence of tonsilar hernia were significantly correlated with long-term sequelae on speech (respectively P = 0.027 and P = 0.05). Initial supratentorial ventricular dilatation was correlated with ability to sustain adequately daily tasks (P = 0.002). On delayed MRI, cerebellar atrophy was inversely correlated with ability to sustain daily tasks (P = 0.002). Hypointense T1 territory in remaining cerebellar parenchyma significantly correlated with immediate post-operative cerebellar syndrome (P = 0.01) and showed a tendency for post-operative mutism (P = 0.087) but was not correlated with any long-term sequelae. Increased cranial pressure on initial MRI and cerebellar atrophy detected on subsequent MRI studies correlated with immediate and long-term cerebellar sequelae.
    No preview · Article · Dec 2010 · Pediatric Blood & Cancer

  • No preview · Article · Jan 2004

  • No preview · Article · Jan 2003 · The Lancet Neurology
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    ABSTRACT: We report two cases of metastases from visceral cancers to pituitary adenomas, and review the literature. Two female patients, aged 75 and 87 years, underwent transesophageal surgery for presumably benign pituitary adenomas. Using extensive immunostaining studies, histopathological examination showed that the surgical specimens from both patients were composed of metastatic deposits within gonadotropin adenomas. Fourteen cases of metastases to pituitary adenomas have been mentioned in 11 reports in the literature. In all cases, the correct diagnosis was made after autopsy or histopathological studies, even in patients known to suffer from visceral malignancies. In our cases, immunohistochemical studies were conclusive in characterizing the two distinct tumor components. The pathogenetic mechanisms favoring the development of metastases in pituitary adenomas are discussed, especially those altering the normal hypophyseal circulation. Neurosurgeons performing pituitary surgery should be aware of the possibility of metastases in pituitary adenomas.
    No preview · Article · Jun 2001 · Surgical Neurology
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    ABSTRACT: Somatostatin receptors (SSts) have been found in a variety of brain tumors, e.g., meningiomas, medulloblastomas and astrocytomas. Our aim was to investigate their expression in ependymomas. Using RT-PCR, expression of mRNA for the different SSt subtypes was analyzed and quantified in 28 ependymomas and correlated with different variables (age, tumor location, histological grade, recurrence and survival). In addition, in 8 cases, protein expression was studied in vitro, using immunohistochemistry, and in vivo, by somatostatin scintigraphy. mRNAs for all 5 subtypes were variably expressed in each ependymoma. The Southern blotting signal obtained after SSt(1) and SSt(2) amplification was higher than that for the other receptor subtypes. No significant correlation was seen between the level of SSt(1) and SSt(2) mRNA expression and age, location, histological grading, recurrence or survival. In the 8 cases, SSt(1) staining was negative in 3 and low in 5. Staining for SSt(2A) was positive but low in every specimen analyzed. SSt(1) and SSt(2) immunoreactivity was seen only in the cytoplasm of tumoral cells. Somatostatin scintigraphy showed clear uptake, which agreed with MRI data in the majority of cases. However, no correlation was seen between tracer uptake intensity and histological grade, SSt(1) and SSt(2) mRNA expression or immunostaining intensity. This evidence for the expression of SSt(2) receptors in ependymomas opens interesting prospects for their follow-up.
    No preview · Article · May 2001 · International Journal of Cancer
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    ABSTRACT: Classical and new therapies in anaplastic astrocytomas and glioblastomas do not yield sufficient results. Agents able to redifferentiate neoplastic cells in vitro are known. We proposed alfacalcidol, a vitamin D analog able to bind to nuclear receptors regulating mitotic activity, in the treatment of malignant gliomas. Patients with glioblastomas and anaplastic astrocytomas were enrolled in a phase II trial involving surgery or biopsy, radiotherapy (64 Gy), chemotherapy with VM26-CCNU or fotemustine, and alfacalcidol at the daily dose of 0.04 microg/kg. MRI took place every 6 months. Eleven patients were included and completed the study. The series involved 10 glioblastomas and 1 anaplastic astrocytoma. Three patients out of 11 patients (27%), 2 glioblastomas and 1 astrocytoma grade III, exhibited a particular response, consisting in the progressive regression of the radiological lesion, with a decrease of the gadolinium-enhanced area. Simultaneously, the patients showed a complete clinical remission, observed respectively for 7, 5 and 4 years. In the series of 10 patients with glioblastomas, 2 cases showed this response; after 4 years, 2 of 10 patients with glioblastomas (20%) were alive; the median survival time is 21 months. Normal or subnormal calcemia was observed, at the dose proposed, so that no interruption of the drug was necessary. Alfacalcidol, an in vitro agent of redifferentiation, is safe and seems able to induce in some patients, in synergy with classical surgery-radiotherapy-chemotherapy treatments, a particular progressive and durable regression of the tumor. The responders might represent about 20% of malignant gliomas.
    No preview · Article · Feb 2001 · Journal of Neuro-Oncology
  • Philippe Bret · Jean Chazal
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    ABSTRACT: Normal pressure hydrocephalus (NPH) is generally considered to be a disorder of the adult and geriatric population. Only a few reports have described the possible occurrence of this condition in children. A series of 16 patients aged less than 20 years forms the basis of the present report. Among these 16 patients, 11 had a clearly identified etiologic factor and 7 had had a shunt previously implanted. The majority of patients exhibited at least two elements of the adult's triad of psychomotor retardation (14 cases) and/or psychotic-like symptoms (4 cases), gait anomalies (8 cases), and sphincter disturbances (3 cases). Six patients had their intracranial pressure (ICP) monitored. ICP values were estimated to be within the normal limits for age. All the 16 patients underwent shunting or shunt revision. Surgical results were as follows (mean follow-up 2017.2 months): a good response to shunting was obtained in 12 cases (cured: 5, improved: 7), while the other 4 patients failed to improve. It seems likely that associated parenchymal disorders have played a major role in therapeutic failures. In children showing ventricular dilation on computed tomographic (CT) analysis and a clinical picture of subtle psychomotor deterioration, it may be difficult to distinguish an active disorder of the CSF dynamics from arrested hydrocephalus. Since intracranial manometry cannot be undertaken as a routine procedure, less invasive methods such as cerebrospinal fluid (CSF) tap test, psychometric or urodynamic tests deserve special attention as reliable predictors of outcome after shunting. Because most patients undergo shunting without prior assessment of their CSF pressure, the term chronic hydrocephalus is proposed as an alternative designation to NPH, since there is little argument for maintaining an instrumentally based definition of the syndrome.
    No preview · Article · Nov 1995 · Child s Nervous System
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    ABSTRACT: In a 31-year-old male patient suffering from progressive myelopathy, a right carotid angiography disclosed an intracranial tentorial arteriovenous fistula (AVF) draining intrathecally into the spinal medullary veins. An embolization via the afferent meningohypophyseal artery was not technically feasible, and a microsurgical excision of the AVF was accomplished via a suboccipital approach, resulting in the angiographic cure of the fistula and progressive relief of the myelopathy. Fourteen reported cases of intracranial dural AVF draining intrathecally are reviewed. In most patients, authors encountered diagnostic difficulties similar to those noted in this case. Surgical and/or endovascular therapeutic methods have provided disappointing results, likely attributable to a prolonged course of spinal cord dysfunction. Pathophysiologically, a mechanism of venous congestion of the cord seems to be involved, as acknowledged by several magnetic resonance and angiographic studies. In patients who appear to have a clinical and myelographic picture of "vascular" myelopathy and who exhibit negative spinal angiography, a four-vessel cerebral angiography should be undertaken, aiming at the recognition of an intracranial AVF.
    No preview · Article · Dec 1994 · Neurosurgery