Cellular haemangioma

Light and electron microscopic studies were conducted on the immature vascular tumors of two infants, containing various stages of differentiation of the blood vessels and both benign haemangioendotheliomas and haemangiopericytomas. We were able to confirm the existance of two kinds of hyperplastic, immature cells i.e. endothelial cells and pericytes in the same tumor. Presence of crystalloid inclusions in the endothelial cells and absence of the Weibel-Palade bodies, as well as a deficiency in factor VIII-related antigen and no tissue fibrinolytic activity, suggested that the endothelial cells in these lesions were immature. Electron microscopic studies appear more decisive in the diagnosis of heterogenous cellular vascular tumors than light microscopy and if available should be used to aid in the final diagnosis. The authors propose that the term cellular haemangioma would be more appropriate in describing this vascular entity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47515/1/428_2004_Article_BF00428503.pd

Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients

The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator. Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1–18 months, with a median follow-up of 6 months. Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3–18 months) with no in-field failures and were able to obtain encouraging toxicity profiles. Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity

Preconditioning-induced ischemic tolerance: a window into endogenous gearing for cerebroprotection

Ischemic tolerance defines transient resistance to lethal ischemia gained by a prior sublethal noxious stimulus (i.e., preconditioning). This adaptive response is thought to be an evolutionarily conserved defense mechanism, observed in a wide variety of species. Preconditioning confers ischemic tolerance if not in all, in most organ systems, including the heart, kidney, liver, and small intestine. Since the first landmark experimental demonstration of ischemic tolerance in the gerbil brain in early 1990's, basic scientific knowledge on the mechanisms of cerebral ischemic tolerance increased substantially. Various noxious stimuli can precondition the brain, presumably through a common mechanism, genomic reprogramming. Ischemic tolerance occurs in two temporally distinct windows. Early tolerance can be achieved within minutes, but wanes also rapidly, within hours. Delayed tolerance develops in hours and lasts for days. The main mechanism involved in early tolerance is adaptation of membrane receptors, whereas gene activation with subsequent de novo protein synthesis dominates delayed tolerance. Ischemic preconditioning is associated with robust cerebroprotection in animals. In humans, transient ischemic attacks may be the clinical correlate of preconditioning leading to ischemic tolerance. Mimicking the mechanisms of this unique endogenous protection process is therefore a potential strategy for stroke prevention. Perhaps new remedies for stroke are very close, right in our cells

Refining the staging evaluation of pineal region germinoma using neuroendoscopy and the presence of preoperative diabetes insipidus1

Treatment strategies for CNS germinoma are currently evolving. Current approaches include reducing the volume and dose of radiation by adding pre-irradiation chemotherapy. Very accurate staging is necessary with such an approach to prevent failures. Eight consecutive patients with pineal germinoma at one institution underwent endoscopic surgery for tumor biopsy, direct visualization of the third ventricular region, and third ventriculostomy for those with hydrocephalus. All patients were treated with 4 cycles of chemotherapy. Conformal field radiation therapy followed, with the dose to the tumor bed dependent on the response to chemotherapy. Patients who had MRI, endoscopic, or cerebrospinal fluid evidence of multicentric or disseminated disease also received craniospinal radiation. Six patients had diabetes insipidus (DI) at presentation. All 6 had tumor studding the floor of the third ventricle on endoscopic visualization, while only 4 of those patients had MRI evidence of disease in that region. All patients have completed therapy and are alive, with no evidence of disease at median follow-up of 31.5 months from diagnosis. Direct endoscopic visualization of the third ventricular region may be more sensitive than MRI for evaluating the presence of suprasellar disease and appears to add important information. This parameter should be added to the staging evaluation when feasible. In this series, the presence of DI was 100% predictive of suprasellar disease, even when the MRI was negative for involvement of that region. Patients should be evaluated for DI as part of the initial staging, and if it is present, the patients should be treated for suprasellar disease regardless of MRI findings