Léiomyome du corps ciliaire

We present our experience with three patients, two of whom were women, 16, 28 and 44 years of age, presenting with leiomyomas of the ciliary body. Salient clinical features were involvement of the left eye and temporal quadrants in two cases and extension into the anterior chamber in the other. Two patients underwent enucleation and the third had iridocyclochoroidectomy. Immunohistochemical studies showed strong positivity for muscle-specific actin, smooth muscle actin and desmin, whereas staining against vimentin, HMB-45 and S-100 protein was negative. Although there are no specific clinical or imaging signs for intraocular leiomyoma, this tumor should be suspected when pigmented ciliary body tumors are encountered, especially in young female patients.

Chronic daily administration of selegiline and EGb 761 increases brain's resistance to ischemia in mice

Brief cerebral ischemia is reported to cause selective neuronal necrosis, apoptotic cell death, silent infarcts and, when recurrent, cognitive decline. Acute administration of selegiline and EGb 761 have been shown to have anti-apoptotic and neuroprotective effects in experimental ischemia. Their daily use is currently advised to slow down cognitive decline in patients with vascular dementia. Hence, unlike previous studies, we studied the neuroprotective action of chronic daily administration of these drugs in Swiss mice subjected to 30-min middle cerebral artery occlusion and 72 h of reperfusion since this model was reported to induce a slowly evolving infarct with profuse apoptotic cell death. Infarct area was evaluated by H&E staining on coronal brain sections and, apoptotic cells were identified by histological criteria, terminal transferase-mediated d-UTP nick-end labeling (TUNEL) and by immunohistochemical detection of caspase-cleaved actin fragments (fractin). Fifty-one mice received daily intraperitoneal injections of 10 mg/kg selegiline (n=18) or 50 mg/kg EGb 761 (n=17) or equal volume of saline (n=16) for 10-14 days before but not on the day of insult. The infarct volume, number of TUNEL- and fractin-positive cells were significantly reduced in treatment groups by 30, 42 and 51% (selegiline) and, 27, 27 and 29% (EGb 761), respectively. These data suggest that prophylactic use of selegiline and EGb 761 could increase the brain's resistance to mild ischemic injury.

Nitric oxide is involved in ischemia-induced apoptosis in brain: a study in neuronal nitric oxide synthase null mice

Nitric oxide can promote or inhibit apoptosis depending on the cell type and coexisting metabolic or experimental conditions. We examined the impact of nitric oxide on development of apoptosis 6, 24, and 72 h after permanent middle cerebral artery occlusion in mutant mice that lack the ability to generate nitric oxide from neuronal nitric oxide synthase. Adjacent coronal sections passing through the anterior commissure were stained with hematoxylin and eosin or terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Immunoblotting was used to identify changes in the anti- and proapoptotic proteins Bcl-2 and Bax, respectively. Activation of caspases was assessed by appearance of actin cleavage products using a novel antiserum directed against 32-kDa actin fragment (fractin). In the neuronal nitric oxide synthase mutant mouse, infarct size and TUNEL positive apoptotic neurons were reduced compared to the wild-type controls. At 6 h, Bcl-2 levels in the ischemic hemisphere were increased in mutants but decreased in the wild-type strain. Bax levels did not change significantly. Caspase-mediated actin cleavage appeared in the ischemic hemisphere at this time point, and was significantly less in mutant brains at 72 h compared to the wild-type. The reduction in the number of TUNEL and fractin positive apoptotic cells appears far greater than anticipated based on the smaller lesion size in mutant mice.Hence, from these data we suggest that a deficiency in neuronal nitric oxide production slows the development of apoptotic cell death after ischemic injury and is associated with preserved Bcl-2 levels and delayed activation of effector caspases.

Cranial infantile myofibromatosis: report of three cases

BACKGROUND

Infantile myofibromatosis is a proliferative disorder of infancy and early childhood characterized by the development of single or multiple nodular lesions arising from cutaneous or subcutaneous tissue, muscle, bone or visceral organs. In approximately one-third of cases, this myofibroblastic proliferation involves the head and neck region.

CASE REPORT

In this paper we report on three cases of cranial infantile myofibromatosis in infants. The clinical presentation and the deceptive histopathological features can make diagnosis difficult.

CONCLUSION

The significance of recognizing this entity is stressed, since its indolent clinical behavior might prevent diagnosis.

Extraneural metastasis in a child with atypical teratoid rhabdoid tumor of the central nervous system

Atypical teratoid rhabdoid tumor is a distinctive brain tumor appearing in infancy and early childhood. Leptomeningeal dissemination is common, both at presentation and relapse. Extracranial metastases of the central nervous system tumors are rarely seen. To our knowledge there is only one report with an atypical teratoid rhabdoid tumor metastasizing via a ventriculoperitoneal shunt. We describe the first case of atypical teratoid rhabdoid tumor of the central nervous system who developed lung metastasis without the presence of a shunt.

Intrapontomesencephalic colloid cyst: an unusual location. Case report

Colloid cysts appear most commonly in the third ventricle; the occurrence of a colloid cyst in the brainstem is very unusual. The authors report on a patient with an intrapontomesencephalic colloid cyst. This 15-year-old girl complained of a headache associated with diplopia. Her neurological examination revealed right-sided sixth nerve paresis and a mild left hemiparesis. Radiological investigations revealed an intraparenchymal pontomesencephalic cystic mass. Surgical removal of the lesion was achieved via the pterional transsylvian approach and the patient experienced an excellent recovery. Histopathological examination revealed that the lesion was a typical colloid cyst. To the best of the authors' knowledge, this is the first case in which an intraparenchymal upper brainstem colloid cyst was surgically excised totally. In addition to describing this case, the authors also review other brainstem neuroepithelial cysts described in the literature and briefly discuss the concept of their origin.

A case of leukoencephalopathy with vanishing white matter

A 6-year old Turkish boy with a recently defined entity: "leukoencephalopathy with vanishing white matter" is described. He was born to consanguinous parents. His psychomotor development was normal till he first presented with fever and generalized tonic-clonic seizures at the age of 2.5, followed by rapid motor and mental deterioration. Decerebrate posture and marked spasticity subsequently developed. The initial MRI examination showed diffuse involvement of white matter, including subcortical U-fibers, with signal intensity parallel to CSF on all sequences. The white matter appeared swollen. The ventricles were slightly enlarged and there was cavum septi pellucidi et vergae. The posterior crus of the internal capsule, external and extreme capsules were affected. Cerebellar hemispheres and vermis showed atrophy. The involvement pattern of brainstem was noteworthy in that pontine tegmentum and cruri cerebri were affected. Follow-up MRI obtained after three years did not show any interval change. Brain biopsy showed thinned cortex with relatively preserved cortical layering and neuronal structure. There was rarefaction of the white matter with cystic degeneration. Fibrillary gliosis and increased number of oligodendroglial cells were observed within the cerebral white matter.

Leigh syndrome in a 3-year-old boy with unusual brain MR imaging and pathologic findings

We report unusual MR serial imaging and electron microscopy findings in a 3-year-old boy who had Leigh syndrome with cytochrome-c oxidase (cox) deficiency. The MR imaging findings included periventricular white matter involvement, posteroanterior progression, and extension through the corpus callosum and internal capsule; however, no basal ganglia or brain stem abnormality was found, which was suggestive of leukodystrophy. The most noteworthy findings were the cystic foci with contrast enhancement in the affected white matter.

Rasmussen encephalitis in childhood

Six patients admitted to the Department of Pediatric Neurology at Hacettepe University Children's Hospital between 1992 and 1997 with a clinical diagnosis of Rasmussen encephalitis received surgical treatment for their intractable epilepsy. MRI, SPECT and WADA tests were performed in patients with an epileptic focus demonstrated on routine or long-term video EEG monitoring. Viral studies using the PCR methodology were performed in cases with histopathological evidence of Rasmussen encephalitis. The ages of these patients ranged between 7 and 16 years, and the mean age at onset of seizures was 7.1+/-2.2 years. In four patients seizures presented as epilepsia partialis continua and were refractory to anticonvulsive drug therapy. In three cases intravenous immunoglobulin therapy yielded temporary and partial improvement in seizure control. The mean presurgical follow-up duration was 2.04+1.74 years, and early surgical intervention for epilepsy was performed in one case. The surgical approach selected for the treatment of epilepsy was resective surgery with electrocorticography. The mean postoperative follow-up duration was 32.3+17.2 months. Seizures were fully controlled in one patient, in whom surgery was performed 3 months after the seizures first started. Early surgical intervention may provide histopathological evidence for diagnosis as well as effective seizure control.

Spinal angiolipoma: case report and review of literature

Spinal extradural angiolipomas are distinct, benign, and rare lesions composed of mature lipocytes admixed with abnormal blood vessels. They account for 0.14% of all spinal axis tumors. The case described here was a 72-year-old patient presenting with a history of paraparesis, hypoesthesia under the T2 level, hyperreflexia, and urinary overflow incontinence that appeared within 7 days after the administration of a coronary vasodilator drug regimen. The spinal magnetic resonance scan showed a lipomatous mass with signal void lesions, suggesting a vascular component of the tumor. The patient improved rapidly after surgical resection of the epidural tumor and decompression of the cord. According to the present literature, the duration of neurological symptoms ranges from 1 to 180 months (mean 28 months). But this patient's neurological deterioration took place 4 days before hospitalization. We believe that this can be explained by the increased tumor blood volume caused by vasodilator drugs, which in turn exerted a pulsatile compressive effect on the cord.

Histopathological changes and nitric oxide synthase activity in corpus cavernosum from rats with neurogenic erectile dysfunction

OBJECTIVE

To investigate changes in histology and nitric oxide synthase (NOS) activity in cavernosal tissues from rats with neurogenic erectile dysfunction induced experimentally.

MATERIALS AND METHODS

Twenty-four adult male Sprague-Dawley rats were divided equally into three groups and underwent a sham operation (control, group 1), unilateral (group 2) or bilateral (group 3) cavernosal nerve resection. Three months later they were killed and the cavernosal tissues analysed histologically by light and transmission electron microscopy, with NOS activity detected using an NADPH-diaphorase staining technique.

RESULTS

On light and electron microscopy, while penile nerves and cavernosal smooth muscle cells had a normal morphological appearance in the eight control rats, there were degenerative changes of the myelinated penile nerves and axonal fibrosis in groups 2 and 3. However, these changes were not significant. Using NADPH-diaphorase staining, NOS activity was detected in all three groups in endothelial cells and cavernosal structures. However, the staining was more intense in endothelial cells and cavernosal muscles of rats in group 2 than in the other groups.

CONCLUSION

NOS activity was increased in the cavernosal tissue after cavernosal denervation, but the pharmacological action of nitric oxide may be impaired.

Atypical central neurocytoma

The proliferative potential of central neurocytomas was determined in a biopsy series of 36 cases and compared with clinical outcome. The mean size of the growth fraction, as determined by MIB-1 labeling index (MIB-1 LI) at first biopsy, was 2.8 +/- 2.5 with a range of 0.1 to 8.6%. Neurocytomas with an MIB-1 LI > 2% comprised 39% of cases and showed a close correlation with the presence of vascular proliferation (p = 0.0006). The Kaplan-Meier analysis showed a highly significant difference in disease-free survival between the 2 groups (p = 0.0068). Over an observation time of 150 months, there was a 22% relapse among patients with an MIB-1 LI less than 2% and a 63% chance of relapse among those with an MIB-1 LI greater than 2%. We propose the term "atypical central neurocytoma" for the latter subset, corresponding to WHO grade II.

Wernicke's encephalopathy with ballooned neurons in the mamillary bodies: an immunohistochemical study

Two cases of Wernicke's encephalopathy with the rare phenomenon of ballooned neurons in the mamillary bodies are reported. Both patients suffered from acute Wernicke's symptoms starting approximately two weeks before death. The mamillary bodies contained grossly enlarged, ballooned neurons, in one case associated with focal necrosis. The affected neurons were immunoreactive for phosphorylated neurofilament (160 and 200 kDa), and synaptophysin. Ubiquitin and alpha beta-crystallin expression were not detected. The mamillo-thalamic tract appeared normal in both cases. There was a marked associated microglial reaction, as shown by the antibody Ki-MIP. It is concluded that the ballooning of mamillary neurons reflects an acute retrograde reaction to primarily axonal damage. Rather than being a rare manifestation of the disease, these cases may constitute a typical intermediate early stage (10-15 days) in the development of Wernicke's encephalopathy).

Central neurocytoma: a synopsis of clinical and histological features

The central neurocytoma is a supratentorial, often calcified brain tumour affecting young adults and is typically located in the lateral ventricles in the region of the foramen of Monro. Clinically, the tumour causes signs of increased intracranial pressure, visual and mental disturbances and, occasionally, pyramidal or endocrine symptoms. By light microscopy, the tumour is composed of small round cells in a delicate fibrillary matrix. Tumour cells consistently show features of neuronal differentiation by electron microscopy (synapses, dense-core vesicles, presynaptic clear vesicles, specialized synaptic junctions) and immunoreactivity for synaptophysin and other neuronal marker proteins. The tumour can be totally removed in nearly half of the cases. After incomplete surgical resection neurocytomas may recur but because of their low proliferation potential, radio- or chemotherapy are not generally recommended. Postoperative recurrence-free survival times of up to 19 years have been reported. Neurocytomas constitute nearly one half of supratentorial intraventricular tumours in adults but amount to less than 1% of all tumours of the central nervous system and its coverings.