Foreign body granuloma associated with dura-cranioplasty after resection of convexity meningioma with extracranial extension: case report.

A 72-year-old man presented with a space-occupying lesion at the site of the prior craniotomy one year after removal of a convexity meningioma with an extracranial extension. The lesion had grown outside the duraplasty with extracranial extension through the degenerative cranioplasty, and was removed. The histological diagnosis was granulation. The original dura-cranioplasty had been performed using Goretex dura substitute, hydroxyapatite cement, and fibrin glue-bonded autologous bone dust. This rare case of foreign body granuloma occurring after craniotomy with dura-cranioplasty indicates that detailed preoperative evaluation of tissue destruction based on neuroimaging is essential for construction of a suitable cranioplasty.

Persistent roles of signal transduction of platelet-derived growth factor B in genesis, growth, and anaplastic transformation of gliomas in an in-vivo serial transplantation model.

We previously reported that retrovirally transduced platelet-derived growth factor-B (PDGFB) in glial progenitors of the rat cerebral white matter, subventricular zone, or brain stem induced malignant brain tumors closely resembling human glioblastoma (GBM). While human GBMs may progress over the period of several months to a few years, prospective, long-term in-vivo observation of histological changes of the tumor tissues is not feasible in these models, because the animals undergo rapid tumor progression and mortality within approximately 1 month. We thus performed successive, long-term in-vivo transplantation of the PDGFB-induced tumor cells into the rat cerebrum. Primary retroviral transduction of PDGFB in the glial progenitors of the rat basal ganglia induced malignant glioma resembling human GBM or anaplastic oligodendroglioma (AOL) consisting of relatively monomorphous tumor cells expressing markers for the oligodendrocyte lineage. In the course of long-term successive transplantation, tumor cells presented pleomorphism as well as focal GFAP expression. This suggests that secondary chromosomal aberration and dysregulation of gene expression following accelerated cell cycle by PDGFB stimulation would induce morphological and immunophenotypic changes in tumor cells. Furthermore, while the primary tumors contained only a minor fraction of proviral GFP-expressing or hemagglutinin-expressing cells, most tumor cells came to express these proviral genes in the course of serial transplantation suggesting a persistent role of PDGFB-expressing cells in maintenance and growth of the tumors. This model would be useful for investigation of the long-term effects of PDGFB stimulation in glioma tissues on anaplastic evolution.

Glial progenitors in the brainstem give rise to malignant gliomas by platelet-derived growth factor stimulation.

Glial progenitors in the white matter and the subventricular zone are the major population of cycling cells in the postnatal central nervous system, and thought to be candidates for glioma-initiating cells. However, less is known about the dividing cell populations in the brainstem than those in the cerebrum, leading to the lag of basic understanding of brainstem gliomas. We herein demonstrate much fewer cycling glial progenitors exist in the brainstem than in the cerebrum. We also show that infecting brainstem glial progenitors with PDGFB-green fluorescent protein (GFP)-expressing retrovirus induced tumors that closely resembled human malignant gliomas. Of note, brainstem tumors grew more slowly than cerebral tumors induced by the same retrovirus, and >80% tumor cells in the brainstem consisted of GFP-positive, infected progenitors while GFP-positive cells in the cerebral tumors were <20%. These indicate that cerebral tumors progressed rapidly by recruiting resident progenitors via paracrine mechanism whereas brainstem tumors grew more slowly by clonal expansion of the infected population. The cerebral and brainstem glial progenitors similarly showed reversible dedifferentiation upon PDGF stimulation in vitro and did not show the intrinsic difference in terms of the responsiveness to PDGF. We therefore suggest that slower, monoclonal progression pattern of the brainstem tumors is at least partly due to the environmental factors including the cell density of the glial progenitors. Together, these findings are the first implications regarding the cell-of-origin and the gliomagenesis in the brainstem.

Pseudoprogression following concurrent temozolomide and radiotherapy in a patient with glioblastoma: findings on functional imaging techniques.

Concurrent temozolomide (TMZ) and radiotherapy became the new standard of care for patients diagnosed with glioblastoma multiforme (GBM). Recently, there has been an increasing awareness of progressive and enhancing lesions on MR images immediately after treatment. These lesions may be a treatment effect, so-called pseudoprogression. We experienced one case pathologically and clinically diagnosed as pseudoprogression. The lesion showed a high apparent diffusion coefficient on diffusion-weighted imaging, low blood volume on perfusion imaging, and low uptake of 18F-fluorodeoxyglucose on positron emission tomography. The lesion was pathologically diagnosed as pseudoprogression after additional surgical resection.

Results of a long-term follow-up after neuroendoscopic biopsy procedure and third ventriculostomy in patients with intracranial germinomas.

OBJECT: The authors report the results of long-term follow-ups in 12 patients with intracranial germinomas who underwent neuroendoscopic procedures before chemotherapy and radiotherapy, and discuss the usefulness and safety of these procedures. METHODS: Between January 1996 and December 2005 at Kyushu University Hospital, 12 patients with intracranial germinomas underwent neuroendoscopic biopsy procedures involving a flexible fiberscope. Eight patients simultaneously underwent endoscopic third ventriculostomy (ETV) for existing obstructive hydrocephalus. All patients received chemotherapy and radiotherapy postoperatively, according to the regimen promulgated by the Japanese Pediatric Brain Tumor Study Group. The patients were followed for an average of 78.6 months (range 15-134 months), and a retrospective study was conducted. RESULTS: Germinomas were histologically verified in all patients. No postoperative deaths or permanent morbidity was related to the neuroendoscopic procedures. No other cerebrospinal fluid diversion, such as that achieved with a ventriculoperitoneal shunt, was needed for the management of hydrocephalus. A complete response to postoperative chemotherapy and radiotherapy was achieved in all cases. Only one patient had a recurrent lesion in the spinal cord 6 years after the initial treatment; however, this patient had undergone only the neuroendoscopic biopsy procedure without ETV. CONCLUSIONS: Neuroendoscopic procedures can permit a precise histological diagnosis of intracranial germinomas and are safe and effective in the management of hydrocephalus associated with these tumors. The risk of tumor dissemination due to the neuroendoscopic procedures appears to be minimal when the appropriate chemotherapy and radiotherapy are provided postoperatively.