Kenichiroh Asano

Meningiomas with brain edema: Radiological characteristics on MRI and review of the literature

OBJECT Despite their benign characteristics, meningiomas are often accompanied by perifocal brain edema. The aims of this study are to determine what kind of characteristics on magnetic resonance (MR) image are indicative of a meningioma that produces brain edema and to investigate the mechanism responsible for brain edema accompanying meningiomas. METHODS Fifty-one patients with meningioma were examined by magnetic resonance imaging (MRI), and tumor size, tumor location, shape of tumor margin, peritumoral rim, and signal intensity of tumor on T2-weighted image (T2WI) were compared and correlated with the presence versus absence of brain edema. Surgical histopathology was also examined and correlated with the MRI findings and brain edema. RESULTS Shape of tumor margin, peritumoral rim, and signal intensity of tumor on T2WI correlated with brain edema on multivariate analyses. CONCLUSION Invasive pattern of brain-tumor interface and hyperintensity on T2WI were indicative factors of meningiomas producing brain edema.

Expression of cadherin and CSF dissemination in malignant astrocytic tumors.

Abstract Cadherins are Ca2+-dependent cell adhesion molecules that play an important role in tissue construction and morphogenesis in multicellular organisms. Because in recent years there have been reports of cadherin involvement in tumor metastasis, we conducted an immunostain for E-cadherin and N-cadherin monoclonal antibodies in paraffin-embedded surgical specimens of primary and recurrent lesions in 13 cases of glioblastoma and nine cases of anaplastic astrocytoma. No expression of E-cadherin was detected in the tumor cells. On the other hand, expression of N-cadherin was observed in malignant astrocytic tumor cells, but the N-cadherin positive rate tended to be less at the time of recurrence. Decreased expression of N-cadherin was detected at the time of recurrence in 11 of the 13 cases in the glioblastoma group. Cerebrospinal fluid (CSF ) dissemination and extracranial metastasis were observed in nine (81.8%) of these 11 patients. Therefore, we tried to analyze the clinical backgrounds and the N-cadherin positive rates by statistics. We concluded that decreased expression of N-cadherin at the time of recurrence correlates with dissemination in malignant astrocytic tumors.

Expression and role of cadherins in astrocytic tumors

Cadherins are Ca2+-dependent cell adhesion molecules that play an important role in tissue formation and morphogenesis in multicellular organisms. In recent years, there have been reports of cadherin involvement in tumor invasion and metastasis. Twenty-two surgical specimens and some cultured cells were studied by immunohistochemical staining. No significant difference was observed in the patients with anaplastic astrocytoma, whereas decreased expression of N-cadherin was detected at the time of recurrence in those with glioblastoma. In these groups, cerebrospinal fluid dissemination was found, and contralateral cerebral metastases and extracranial metastases were observed. We conclude that decreased N-cadherin expression at the immunohistochemically demonstrated time of recurrence correlates with tumor invasion and dissemination of cerebrospinal fluid.

Usefulness of thallium-201 SPECT in the evaluation of tumor natures in intracranial meningiomas

IntroductionAlthough intracranial meningiomas are regarded as benign tumors, some of them behave clinically as malignant tumors. Past reports suggest that MIB 1 and vascular endothelial growth factor (VEGF) in postoperative tumor specimens correlate with the aggressive nature of tumors, but preoperative prediction of such a nature is more useful for therapeutic planning for the tumor. The purpose of this study was to assess the usefulness of preoperative thallium-201 chloride single-photon emission computed tomography (Tl SPECT) to evaluate biological behavior in intracranial meningiomas.MethodsTl SPECT was performed on 39 patients with intracranial meningioma and Tl uptake indices were calculated. The difference in the Tl uptake index between atypical meningiomas and other pathological types of meningioma was evaluated. Moreover, correlation of Tl uptake indices with the MIB1 labeling index was estimated. Tl uptake indices were also compared between VEGF strongly positive and weakly positive meningiomas.ResultsThe delayed index of atypical meningioma was significantly higher than that of the other pathological types (p = 0.036). Significant correlation was found between the Tl uptake index in the delayed image and MIB1 labeling index (p < 0.0001, R2 = 0.36). Moreover, VEGF strongly positive meningiomas exhibited a significantly higher Tl uptake index compared to VEGF weakly positive meningiomas in both the early image and the delayed image (p = 0.029, 0.023, respectively).ConclusionsTl uptake index may be a possible preoperative surrogate marker of MIB1 and VEGF that is useful in detecting aggressive natures in intracranial meningiomas.

A case of endolymphatic sac tumor with long-term survival.

A 72-year-old man developed left facial palsy at age 14 and left-sided hearing loss at age 20. At the age of 59, he presented with gait disturbance, and a large left cerebellopontine angle tumor was detected, which had markedly destroyed the pyramidal bone. The tumor was subtotally resected, but he required two more operations at the ages of 64 and 69 because of tumor regrowth. At the present time, recurrent tumor has destroyed the occipital bone and is invading the scalp. However, eventhough he has several cranial nerve palsies and cerebellar ataxia, he remains in stable condition and demonstrates long-term survival. The patients surgical specimens revealed a papillary adenoma, which was recently thought to be of endolymphatic sac origin, although the origin of this kind of tumor, whether arising from the middle ear or from the endolymphatic sac, has not been established with certainty so far. In this paper, we provide further evidence that this tumor originates from the endolymphatic sac, based on anatomical, histopathological, and embryological evidence.

Augmentation index is related to white matter lesions

The augmentation index (AIx) is a measure of pulse wave reflection from peripheral muscular conduit arteries, and is assumed to increase with stiffened arteries. A white matter lesion (WML) is generally regarded as a chronic ischemic lesion, which is associated with cerebral small-vessel arteriosclerosis. The aim of this study is to elucidate the effect of pulse wave reflection on the brain. Carotid AIx was measured in a total of 205 neurologically normal adults. The correlations between AIx and WML were investigated. Two categories of WML were evaluated, periventricular hyperintensity (PVH) and deep and subcortical white matter hyperintensity (DSWMH). On univariate analysis, AIx was significantly correlated with the grades of PVH and DSWMH (P=0.0001, respectively). On multivariate analysis, AIx was correlated with PVH and DSWMH, independent of other risk factors such as age or blood pressure. Pulse wave reflection from small vessels may influence the genesis of WML.

A petrous bone destructive acoustic neurinoma: a tumor of far-lateral origin?

We report a case of an acoustic neurinoma that recurred more than 11 years after “total” tumor removal through the posterior cranial fossa. Recurrent tumor had obliterated the petrous bone, filled the middle ear, and was visible grossly at the external auditory meatus. The unique behavior of this tumor implied that the site of origin was within the labyrinth, beyond the fundus of the internal auditory canal and far lateral to the usual site of acustic neurinoma origin. We offer an hypothesis as to why these tumors occasionally recur, even after clinical “total” removal.