Endoscopic management of pediatric sinonasal schwannoma: case report.

OBJECTIVES: To describe an extremely rare pediatric sinonasal schwannoma, and to reviewmanagement strategies and relevant literature. METHODS: Case report of pediatric sinonasal schwannoma, that was imaged with computed tomography and magnetic resonance imaging and managed endoscopically. Immunohistochemical analysis was performed to determine pathology. RESULTS: A 12-year-old girl presented with a 2-month history of progressive left exophthalmos. Imaging studies showed a large heterogeneous tumour arising from the ethmoid sinus and extending to the base of the skull and to the orbital cavity. The lesion was removed with an endonasal radical excision. The final pathological diagnosis was schwannoma. There was no tumour recurrence or any major complication during the 2-year follow up. CONCLUSION: Schwannoma should be considered in the differential diagnosis for pediatric patients with intranasal masses. Depending on the location and extent of the tumour, endonasal endoscopic excision could be a suitable management strategy.

Kinetics of catalytic oxidation of benzene, n-hexane, and emission gas from a refinery oil/water separator over a chromium oxide catalyst.

With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr2O3) catalyst, of n-hexane, benzene, and an emission air/vapor mixture collected from an oil/water separator of a refinery. Reactions were carried out by controlling the feed stream to constant VOC concentrations and temperatures, in the ranges of 1300-14,700 mg/m3 and 240-400 degrees C, respectively. The destruction efficiency for each of the three VOCs as a function of influent gas temperature and empty bed gas residence time was obtained. Results indicate that n-hexane and the oil vapor with a composition of straight- and branch-chain aliphatic hydrocarbons exhibited similar catalytic incineration effects, while benzene required a higher incineration temperature or longer gas retention time to achieve comparable results. In the range of the VOC concentrations studied, at a given gas residence time, increasing the operating temperature of the catalyst bed increased the destruction efficiency. However, the much higher temperatures required for a destruction efficiency of over 99% may be not cost-effective and are not suggested. A first-order kinetics with respect to VOC concentration and an Arrhenius temperature dependence of the kinetic constant appeared to be an adequate representation for the catalytic oxidation of these volatile organics. Activation energy and kinetic constants were estimated for each of the VOCs. Low-temperature destruction of the target volatile organics could be achieved by using the Cr2O3 catalyst.

Intracranial fatigable ptosis.

Two patients sought treatment for bilateral fatigable ptosis; one patient had a hematoma, and the other patient had an intracranial metastasis. Compression of the central caudal nucleus in the dorsal midbrain is proposed as the cause of this ptosis, and an alteration of central acetylcholine neurotransmission may contribute to ocular fatigability. Because symptoms that suggest fatigable ptosis can be similar to those that suggest ocular myasthenia gravis, a careful evaluation is necessary to avoid misinterpretation.

Magnetic resonance images of neuronal migration anomalies.

Neuronal migration anomalies are a spectrum of brain malformations caused by insults to migrating neuroblasts during the sixth week to fifth month of gestation. To study the characteristics of MRI findings in migration anomalies, MR images of 36 patients (28 children and 8 adults) with migration anomalies were evaluated. Five patients had lissencephaly, eight had pachygyria, twelve had schizencephaly, six had heterotopias of gray matter, three had hemimegalencephaly, and two had polymicrogyria. The frequency of migration anomalies was 0.51% of all cranial MRI studies and 1.21% of pediatric cranial MRI studies at our hospital. The major clinical presentations of these patients were seizure (64%), development delay (42%), motor deficits (42%) and mental retardation (25%). Twenty-five patients (69%) associated with other brain anomalies, including: other migration anomalies in 12 cases (33%), absence of the septum pellucidum in 10 cases (28%), Dandy-Walker malformation/variant in 5 cases, arachnoid cyst in 4 cases, agenesis of the corpus callosum in 3 cases, holoprosencephaly in 2 cases, mega cisterna magna in 1 case and cephalocele in 1 case. Some of them presented with multiple complicated anomalies. As MR imaging provides superb gray-white matter distinction, details of cortical anatomy and multiplanar capability, it can clearly delineate the detail morphologic changes of the brain caused by neuronal migration disorders as well as the associated anomalies.

Mandibular arteriovenous malformation diagnosed by MR and MRA: a case report.

A case of mandibular arteriovenous malformation (AVM) is presented. Prompt diagnosis and appropriate management are essential due to massive bleeding or even death after dental extraction or biopsy. Angiography remains the gold standard in detecting the lesion. Magnetic resonance (MR) imaging with spin-echo sequences reveals the vascular malformation as signal-void. MR angiography can demonstrate the nidus, dilated artery and vein. MR imaging and MR angiography can supplement angiography in the diagnosis of mandibular AVM.

Computed tomography and magnetic resonance imaging of intracranial ependymomas.

We evaluated the neuroimages of 18 pathologically proven cases of ependymoma, 15 cases by CT evaluation and 9 cases by MRI evaluations. In 7 cases of supratentorial ependymomas, 4 were intraparenchymal and 3 were intraventricular ependymomas originating from the ependymal lining layer, the floor of the lateral ventricle, which was best demonstrated on a sagittal MR image. For the cases of infratentorial ependymomas, all were intraventricular. Evidence of seeding through the cerebrospinal fluid pathway to the basal cisterns, spinal cord or ventricles was presented in 6 cases which were particularly well demonstrated in the sagittal section with gadolinium-DTPA enhanced MR imaging. On CT scan, isodense tumors with various portions of high enhancement within a moderate enhancement mass were the most frequent features. In MRI, isointensity relative to gray matter on T1-weighted images and hyperintensity on mild and heavy T2-weighted images were most frequently seen. The signal heterogeneity representing soft tissue, small cysts, necrosis, calcification, vessels or hemosiderin was better visualized in MRI which offered a better assessment of the character of tumor compositions. The soft tissue mass, calcification and cysts as revealed in both CT and MRI are nonspecific, but the location, ages, CSF seeding and particularly, superior MR images can offer very important clues for the diagnosis of ependymoma.

[Metastasis involving the leptomeninges and ventricles of the brain--CT evaluation].

The diagnosis of leptomeningeal or ventricular metastasis by cranial computerized tomography (CT) contributes to earlier treatment and sometimes alters the management of patients with intra- or extra-cranial malignancy. In 20 cases whose metastasis were spreaded via CSF seeding, the abnormal CT findings were 1) mass or nodule in the ventricles or subarachnoid space, 2) ependymal, subependymal enhancement, 3) sulcal, gyral or cisternal enhancement, 4) hydrocephalus not related to the obstruction of primary tumor, 5) falx or tentorial enhancement. In another 8 cases, the metastasis developed through hematogeneous spreading to the choroid plexus or paraventricular parenchyma. The mass or nodule within the ventricles could be well identified with enhanced CT scan. The involved ventricles, in order of frequency, were lateral, 3rd, and 4th ventricles in our series.

MRI manifestations of leptomeningeal metastasis.

Twenty-six cases with leptomeningeal metastasis were analyzed and Gd-DTPA enhanced MR imaging was found to be the most useful tool for making the diagnosis. The important manifestations in order of frequency were: 1) leptomeningeal enhancement; 2) ependymal enhancement; 3) plaque, nodule or mass in the subarachnoid space or ventricles; 4) nerve root thickening; and 5) ventricular dilatation not related to the obstruction of the primary neoplasm. A review of the literature has shown that intracranial leptomeningeal metastasis from spinal cord astrocytoma are very rare. In our series, 3 cases with primary brain tumors developed spinal subarachnoid involvement. This paper also reviews 1 case with thoracic cord astrocytoma which developed multiple intracranial leptomeningeal metastasis.

Ventricular tumors--CT evaluations of 28 cases.

Ventricular neoplasms can be grouped together as a single disease entity because of the behavior of some of the tumors and similarities between the access of therapy and procedure of operation. In our series, the incidence of various ventricular neoplasms (shown in decreasing order) were metastasis, astrocytoma, ependymoma, meningioma, choroid plexus papillomas and oligodendroglioma. The intraventricular tumors included some metastasis involved by hematogenous spread, meningioms, and choroid plexus papilloma while paraventricular tumors included some of the systemic myeloproliferative disorders with ventricular seeding along with tumors with glial origins. Most of the patients with symptoms of intraventricular tumors also had symptoms related to increased intracranial pressure while those with paraventricular neoplasm presented symptoms related to focal signs or symptoms. CT scan with enhancement could provide a very good image modality except in some involvements in the posterior cranial fossa.

[High-resolution computed tomography evaluation of congenital anomalies of the temporal bone].

High-resolution computed tomography (HRCT) was used to study 23 patients with congenital temporal bone deformities. One patient had an inner ear abnormality and 3 patients were combined together with inner, middle and external ear malformations. Embryological development of the outer and middle ears is linked. Development of the inner ear occurs independently. These abnormalities included vestibule dilatation in 2 patients, a lateral semicircular canal defect in 1 case, dilatation of lateral and superior semicircular canals in 1 patient, only dilatation of the lateral semicircular canal in 1 case, oval-window non-development in 3 cases, oval aqueduct dilatation in 1 patient and inner ear abnormalities in 1 case. The study also included 17 cases of unilateral external auditory canal atresia, 5 cases of bilateral atresia, and 1 normal external auditory canal. There were 8 cases of unilateral and 2 cases of bilateral bony atresia. There were 9 unilateral and 1 bilateral cases of membranous atresia. Two cases had bony atresia on one side, with contralateral membranous atresia on the other. Nine unilateral and 2 bilateral cases were positioned superiorly and posteriorly of the mandibular condyle. Thick atresic plate were found in 10 unilateral and 2 bilateral cases. Small tympanic cavities were found in 12 unilateral and 2 bilateral patients; 7 unilateral and 2 bilateral cases had acellular and hypoplastic mastoids. Ossicular deformities were seen in 14 unilateral and 2 bilateral patients. One patient had no ossicle. Anteriorly located descending facial nerve canal was noted in 9 unilateral and 2 bilateral cases. Congenital cholesteatoma was identified in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)