Histopathological Composition of Thrombus in Acute Ischemic Stroke May Vary Even Within the Same Patient: A Preliminary Study Examining Clots According to Their Area of Retrieval.

Objective: Mechanical thrombectomy enables histopathological examination of clots in patients who have suffered acute ischemic strokes. Many studies have described about the relationship between the histopathological compositions of retrieved thrombi and imaging findings, clinical outcomes, and stroke etiology without consensus. In this study, we examined the histological composition of thrombi according to their retrieval site and methods. Methods: We divided retrieved clots into three parts (those retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter) and then histopathologically analyzed their compositions by measuring the area occupied by red blood cells (RBCs), fibrin/platelets (F/Ps), and white blood cells (WBCs). Results: Each specimen showed various composition even within the same patient. For example, the area occupied by RBCs was 20.9% ± 12.1%, 30.5% ± 13.5%, and 41.3% ± 16.1% in the clot retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter, respectively. Conclusion: Histopathological clot composition may vary even within the patient. Further research is needed to investigate more objective methods of histopathological analysis and their clinical significance.

Low tumor cell content predicts favorable prognosis in germinoma patients.

BACKGROUND: Germinoma preferentially occurs in pediatric and young adult age groups. Although they are responsive to treatment with chemotherapy and radiation, the treatment may cause long-term sequelae in their later lives. Here, we searched for clinical and histopathological features to predict the prognosis of germinoma and affect treatment response. METHODS: A total of 114 germinoma cases were included in the analysis. We investigated the association between clinical factors, tumor cell content, and progression-free survival (PFS). RESULTS: The tumor cell content was widely distributed from <5% to 90% in the specimens, with a median value of 50%. Female patients showed higher tumor cell content in the specimens (P = .002). Cases with lesions at atypical sites showed shorter PFS than those with lesions at other sites (P = .03). Patients with a higher tumor cell content (≥50%) showed shorter PFS than those with a lower tumor cell content (<50%) (P = .03). In multivariate analysis, tumor cell content was the only statistically significant prognostic factor (P = .04). Among the 7 cases treated with local radiation and chemotherapy, all 3 cases that recurred (2 outside of the radiation field, 1 unknown) had tumor cell content of ≥50% in the original specimen, whereas all 4 cases without recurrence had tumor cell contents of <50%. CONCLUSIONS: We found that tumor cell content significantly affected the prognosis of germinomas. Although validation of these results using an independent and larger cohort is necessary, this potentially opens the possibility of leveraging this pathological factor in future clinical trials when stratifying the treatment intensity.

Necessity for craniospinal irradiation of germinoma with positive cytology without spinal lesion on MR imaging-A controversy.

BACKGROUND: Cerebrospinal fluid (CSF) cytology and spinal MR imaging are routinely performed for staging before treatment of intracranial germinoma. However, the interpretation of the results of CSF cytology poses 2 unresolved clinical questions: (1) Does positive CSF cytology correlate with the presence of spinal lesion before treatment? and (2) Is craniospinal irradiation (CSI) necessary for patients with positive CSF cytology in the absence of spinal lesion? METHODS: Multicenter retrospective analyses were performed based on a questionnaire on clinical features, spinal MR imaging finding, results of CSF cytology, treatments, and outcomes which was sent to 86 neurosurgical and 35 pediatrics departments in Japan. Pretreatment frequencies of spinal lesion on MR imaging were compared between the patients with positive and negative cytology. Progression-free survival (PFS) rates were compared between patients with positive CSF cytology without spinal lesion on MR imaging treated with CSI and with whole brain or whole ventricular irradiation (non-CSI). RESULTS: A total of 92 germinoma patients from 45 institutes were evaluated by both CSF cytology and spinal MR images, but 26 patients were excluded because of tumor markers, the timing of CSF sampling or incomplete estimation of spinal lesion. Of the remaining 66 germinoma patients, spinal lesions were equally identified in patients with negative CSF cytology and positive cytology (4.9% and 8.0%, respectively). Eleven patients treated with non-CSI had excellent PFS comparable to 11 patients treated with CSI. CONCLUSION: CSI is unnecessary for germinoma patients with positive CSF cytology without spinal lesions on MR imaging.

So-called bifocal tumors with diabetes insipidus and negative tumor markers: are they all germinoma?

BACKGROUND: The Delphi consensus statements on the management of germ cell tumors (GCTs) failed to reach agreements on the statement that the cases with (i) pineal and neurohypophyseal bifocal lesion, (ii) with diabetes insipidus, and (iii) with negative tumor markers can be diagnosed as germinoma without histological verification. To answer this, multicenter retrospective analysis was performed. METHODS: A questionnaire on clinical findings, histological diagnosis, and details of surgical procedures was sent to 86 neurosurgical and 35 pediatrics departments in Japan. RESULTS: Fifty-one institutes reported 132 cases that fulfilled the 3 criteria. Tissue sampling was performed in 91 cases from pineal (n = 44), neurohypophyseal (n = 32), both (n = 6), and distant (n = 9) lesions. Histological diagnosis was established in 89 cases: pure germinoma or germinoma with syncytiotrophoblastic giant cells in 82 (92.1%) cases, germinoma and mature teratoma in 2 cases, and granulomatous inflammation in 2 cases. Histological diagnosis was not established in 2 cases. Although no tumors other than GCTs were identified, 3 (3.4%) patients had non-germinomatous GCTs (NGGCTs). None of the patients developed permanent complications after endoscopic or stereotactic biopsy. Thirty-nine patients underwent simultaneous procedure for acute hydrocephalus without permanent complications, and hydrocephalus was controlled in 94.9% of them. CONCLUSION: All patients who fulfilled the 3 criteria had GCTs or granulomatous inflammation, but not other types of tumors. However, no fewer than 3.4% of the patients had NGGCTs. Considering the safety and the effects of simultaneous procedures for acute hydrocephalus, biopsy was recommended in such patients.

The Histopathological Findings of Two Nonbranching Saccular Cerebral Aneurysms.

Cerebral aneurysms arising from nonbranching sites are different from ordinary branching aneurysms in clinical course and histology. We pathologically examined two cases of saccular aneurysm occurring at nonbranching sites. One was a pseudoaneurysm arising at a branch of the right pericallosal artery. The other had an entirely hyalinized and thickened aneurysmal wall. Despite similar angiographical findings, our two cases had different pathological features as described above. Based on the pathological findings obtained from these cases, we believe that aneurysms in nonbranching sites are caused by injury to the internal elastic lamina. A ruptured aneurysm may be discovered as a blood blister-like aneurysm, whereas an unruptured one may develop into a "nonbranching true aneurysm."

Integrated clinical, histopathological, and molecular data analysis of 190 central nervous system germ cell tumors from the iGCT Consortium.

BACKGROUND: We integrated clinical, histopathological, and molecular data of central nervous system germ cell tumors to provide insights into their management. METHODS: Data from the Intracranial Germ Cell Tumor Genome Analysis (iGCT) Consortium were reviewed. A total of 190 cases were classified as primary germ cell tumors (GCTs) based on central pathological reviews. RESULTS: All but one of the cases that were bifocal (neurohypophysis and pineal glands) and cases with multiple lesions including neurohypophysis or pineal gland were germinomas (34 of 35). Age was significantly higher in patients with germinoma than other histologies. Comparison between tumor marker and histopathological diagnoses showed that 18.2% of histopathologically diagnosed germinomas were marker positive and 6.1% of non-germinomatous GCTs were marker negative, suggesting a limitation in the utility of markers or histopathology alone using small specimens for diagnosis. Comparison between local and central histopathological diagnoses revealed a discordance of 12.7%. Discordance was significantly less frequent in biopsy cases, implying difficulty in detecting all histopathological components of heterogeneous GCTs. Germinomas at the typical sites (neurohypophysis or pineal gland) showed a better progression-free survival than those at atypical sites (P = 0.03). A molecular clinical association study revealed frequent mitogen-activated protein kinase (MAPK) pathway mutations in males (51.4% vs 14.3%, P = 0.007), and phosphatidylinositol-3 kinase/mammalian target of rapamycin (PI3K/mTOR) pathway mutations in basal ganglia cases (P = 0.004). Basal ganglia cases also had frequent chromosomal losses. Some chromosomal aberrations (2q, 8q gain, 5q, 9p/q, 13q, 15q loss) showed potential prognostic significance. CONCLUSIONS: The in-depth findings of this study regarding clinical and molecular heterogeneity will increase our understanding of the pathogenesis of this enigmatic tumor.

Interferon-ß and temozolomide combination therapy for temozolomide monotherapy-refractory malignant gliomas.

Interferon-ß (IFN-ß) has been found to downregulate O6-methyl-guanine-DNA methyltransferase and sensitize glioma cells to chemoradiation therapy. The effectiveness of IFN-ß and temozolomide (TMZ) combination therapy for newly diagnosed glioblastomas was previously reported. However, there is no clinical report of recurrent of malignant gliomas treated with the combination of IFN-ß and TMZ. In the present study, we reported 7 cases of gliomas classified as uncontrollable with adjuvant TMZ monotherapy, who were then treated with IFN-ß and TMZ combination therapy. The magnetic resonance imaging findings and clinical symptoms improved in the majority of the cases, with tolerable adverse events and minimal residual disability. The overall survival (OS) time from the date of the initial surgery exceeded 13 months, suggesting that this combination therapy was successful in improving the prognosis of malignant gliomas refractory to adjuvant TMZ monotherapy.

Potent tumor tropism of induced pluripotent stem cells and induced pluripotent stem cell-derived neural stem cells in the mouse intracerebral glioma model.

Although neural and mesenchymal stem cells have been well-known to have a strong glioma tropism, this activity in induced pluripotent stem cells (iPSCs) has not yet been fully studied. In the present study, we tested tumor tropic activity of mouse iPSCs and neural stem cells derived from the iPSC (iPS-NSCs) using in vitro Matrigel invasion chamber assay and in vivo mouse intracranial tumor model. Both iPSC and iPS-NSC had a similar potent in vitro tropism for glioma conditioned media. The migrated iPSCs to the gliomas kept expressing Nanog-GFP gene, suggesting no neuronal or glial differentiation. iPSCs or iPS-NSCs labeled with 5-bromo-2-deoxyuridine were intracranially implanted in the contralateral hemisphere to the GL261 glioma cell implantation in the allogeneic C57BL/6 mouse. Active migration of both stem cells was observed 7 days after implantation. Again, the iPSCs located in the tumor area expressed Nanog-GFP gene, suggesting that the migrated cells were still iPSCs. These findings demonstrated that both iPSCs and iPS-NSCs had potent glioma tropism and could be candidates as vehicles in stem cell-based glioma therapy.

Effect of boron neutron capture therapy for recurrent anaplastic meningioma: an autopsy case report.

A 70-year-old woman died of systemic metastasis from anaplastic meningioma and underwent autopsy. The patient underwent twice total removal of the right sphenoid ridge meningioma 2 years ago. The tumor recurred 3 times, and then stereotactic radiotherapy was employed. Boron neutron capture therapy (BNCT) was performed for the fourth local recurrence and an additional new lesion. Proliferative activity of the newly developed meningioma, which had been treated with BNCT only, was significantly lower than that of untreated metastatic liver tumor, as well as that of the meningioma specimen obtained at the second surgery. Our pathological findings demonstrated, for the first time, the therapeutic effect of BNCT on anaplastic meningioma at an early stage (2.5 months).

Primary neurolymphomatosis of the lower cranial nerves presenting as Dysphagia and hoarseness: a case report.

Primary neurolymphomatosis is an extremely rare tumor. We report the case of a 74-year-old patient presenting with dysphagia and hoarseness. Initial contrast-enhanced computed tomography of the head, neck, and chest did not reveal any lesions. His symptoms improved with short-term administration of prednisone but recurred and deteriorated. Magnetic resonance (MR) imaging revealed a tumor along the ninth and tenth cranial nerves across the jugular foramen. Fluorine-18 fluorodeoxyglucose positron emission tomography indicated this was a primary tumor. Repeated MR imaging after 2 months revealed considerable tumor enlargement. A left suboccipital craniotomy was performed to remove the tumor that infiltrated the ninth and tenth cranial nerves. The histopathologic diagnosis was diffuse large B-cell lymphoma. Although focal radiation therapy was administered to ensure complete eradication of the tumor, the patient died of aspiration pneumonia with systemic metastasis. To our knowledge, this is the first reported case of primary neurolymphomatosis in the lower cranial nerves.

Pancreatic metastases of cerebellar hemangiopericytoma occurring 24 years after initial presentation: report of a case.

Hemangiopericytoma (HPC) preferentially developing in soft tissues and the meninges has been gradually recognized to be an aggressive, highly metastatic tumor. We herein report the case of a 65-year-old male with pancreatic metastases of cerebellar HPC that developed following two resections of intracranial local recurrent foci, 24 years after the initial craniotomy and 7 years after resection of metastases to the lungs and kidneys. Follow-up abdominal computed tomography scanning and magnetic resonance imaging revealed a solitary tumor in the pancreatic body. Since no other recurrent foci were detectable, distal pancreatectomy was performed. Another metastasis was incidentally found in the resected pancreas. Both foci were pathologically proven to be metastases of HPC. Among the 12 reported cases of pancreatic metastases of HPC, including ours, this case showed the longest duration between initial onset and the development of pancreatic metastases, suggesting that providing long-term follow-up is necessary for HPC patients.

An autopsy case of the Marburg variant of multiple sclerosis (acute multiple sclerosis).

We herein report an autopsy case of the Marburg variant of multiple sclerosis (MS). A 29-year-old woman developed acute and progressive neurological symptoms. A diagnosis of MS was suspected based on the patient's clinical background and brain MRI findings and the lack of evidence of malignancy on a brain biopsy. Despite the administration of typical treatment for MS, a fatal outcome occurred three months after disease onset. The autopsy revealed multiple inflammatory demyelinating lesions in the central nervous system. In addition, two noteworthy histopathological features were observed compared with prototypical MS. We evaluate the pathogenic differences between the Marburg type and prototypical MS by discussing the neuropathology and cerebrospinal fluid (CSF) findings of our case.

Bystander effect in glioma suicide gene therapy using bone marrow stromal cells.

An established rat intracranial glioma was successfully treated through the tumoricidal bystander effect generated by intratumoral injection of rat bone marrow stromal cells (BMSCs) transduced with the herpes simplex virus-thymidine kinase gene (BMSCtk cells) followed by systemic ganciclovir administration. In the present study, we tested the bystander effect of this treatment strategy when using human BMSCs as the vector cells. Human BMSCtk cells were mixed with various kinds of brain tumor cell lines (human and rat glioma cells) and examined in vitro and in vivo tumoricidal bystander effects, by co-culture study and co-implantation study in the nude mouse, respectively. A significant in vitro bystander effect was observed between human BMSCtk cells and any of the tumor cells examined in the ganciclovir-containing medium. A potent in vivo bystander effect against human and rat glioma cells was also demonstrated when ganciclovir was administered. Migratory activity of the human BMSCs toward the tumor cells was enhanced by the conditioned media obtained from both human and rat glioma cells compared to the fresh media. The results of this study have demonstrated that the bystander effect generated by BMSCtk cells and ganciclovir is not cell type-specific, suggesting that the strategy would be quite feasible for clinical use.

Disproportionately large communicating fourth ventricle associated with syringomyelia and intradural arachnoid cyst in the spinal cord successfully treated with additional shunting. Case report.

A 44-year-old woman presented with a rare case of disproportionately large communicating fourth ventricle (DLCFV) associated with syringomyelia and intradural arachnoid cyst in the spinal cord. Ventriculoperitoneal shunt operation was performed for hydrocephalus after subarachnoid hemorrhage. She developed DLCFV, which was then associated with syringomyelia and spinal intradural arachnoid cyst. Shunting of the fourth ventricle improved DLCFV, and then the syringomyelia and arachnoid cyst. Although the aqueduct was patent, independent pressure control of the fourth ventricle and the other ventricles was necessary to improve the symptoms. Shunting of the fourth ventricle should be considered for patients with DLCFV when the symptoms persist despite adequate pressure control of the other ventricles.

Molecular targeting therapy against promyelocytic leukemia protein using arsenic acids in experimental intracranial medulloblastoma.

Our previous study using human Daoy medulloblastoma cells showed that the promyelocytic leukemia (PML) gene was significantly upregulated (2.5-fold) in cells positive to prominin-1 antigen (CD133), a possible marker for cancer initiating cells. Arsenic trioxide (As(2)O(3)) is known to degrade PML protein and has been used for the treatment of patients with acute PML. In the present study, the effect of PML targeting therapy with As(2)O(3) and cytarabine (Ara-C) on Daoy medulloblastoma cell proliferation was investigated. Daoy cells were pretreated with As(2)O(3) for 6 weeks. The As(2)O(3)-pretreated Daoy cells were cultured in medium containing Ara-C and cell viability was examined. Next, the As(2)O(3)-pretreated Daoy cells were inoculated into the nude mouse brain and the effect of Ara-C on the tumor size was evaluated. A significant increase in chemosensitivity to Ara-C was observed in the As(2)O(3)-pretreated Daoy cells in both in vitro and in vivo conditions. PML and CCND1 (cyclin D1) protein expression of Daoy medulloblastoma cells was downregulated by As(2)O(3) treatment. PML has been proposed as a novel therapeutic target to eradicate quiescent leukemia-initiating cells, and PML-expressing CD133-positive cells are similarly a potential therapeutic target of treatment for medulloblastoma.

Chronic subdural hematoma in a patient with congenital afibrinogenemia successfully treated with fibrinogen replacement.

A 37-year-old woman with congenital afibrinogenemia presented with chronic subdural hematoma (CSDH) manifesting as severe headache, nausea, and somnolence after a minor head trauma. Brain computed tomography scans showed a right subdural hematoma associated with midline shift. Laboratory studies showed prolongation of prothrombin time, activated partial thromboplastin time, and undetectably low level of fibrinogen. Until the present episode, she had received plasma-derived fibrinogen concentrate around menstruation and pregnancy. She had also suffered from spinal cord infarction due to vertebral artery occlusion. Burr-hole evacuation and drainage of CSDH was successfully performed using fibrinogen concentrate. The development of CSDH with afibrinogenemia is very rare. Although the past repeated administrations of fibrinogen concentrate were suspected to generate CSDH, paradoxical thrombotic complications caused by upregulation of prothrombin activation, thrombin generation, and growth factors released from platelets might be related to the development of CSDH with congenital afibrinogenemia.

Timing of ganciclovir administration in glioma gene therapy using HSVtk gene-transduced mesenchymal stem cells.

BACKGROUND: An established C6 glioma was successfully treated with intratumoral injection of mesenchymal stem cells transduced with HSVtk gene (MSCtk) and systemic administration of ganciclovir (GCV). The best timing of GCV administration after the MSCtk implantation was studied. MATERIALS AND METHODS: GCV administration was started from 2 days before and 1, 3 and 7 days after the MSCtk administration under both in vitro and in vivo conditions. RESULTS: The C6 cells were completely eradicated in vitro when GCV administration was started from day -2, 1, and 3. Animals with intracranial tumor survived longer when GCV was administered earlier after MSCtk administration. This may, mainly, reflect the difference in the MSCtk/C6 ratio at the time of GCV administration because this ratio drastically decreases during the delay of GCV administration. CONCLUSION: When using a slowly growing vector cell as MSCtk, GCV should be administered soon after MSCtk implantation.

Tumoricidal bystander effect in the suicide gene therapy using mesenchymal stem cells does not injure normal brain tissues.

In our previous rat study, an established intracranial C6 glioma was successfully treated using intratumoral injection of mesenchymal stem cells transduced with the herpes simplex virus-thymidine kinase gene (MSCtk) and systemic administration of ganciclovir (GCV). In the present study, effect of the "bystander effect" associated with the MSCtk/GCV strategy on the background normal brain tissues was examined in both in vitro and in vivo conditions. Rat MSCtk and C6 glioma cells were mixed and seeded on the rat primary neuron and glia co-culture in the medium containing GCV to generate the bystander effect and the numbers of background cells were counted on day 0, 2 and 7. Though the number of MSCtk and C6 cells decreased rapidly due to the bystander effect, most of the neurons and glias survived on day 7. Next, rats were intracranially injected with the MSCtk and C6 cells and then intraperitoneally administered with GCV for 7days. No remarkable histological abnormality including apoptosis was observed in the background brain tissues near the injection site. The present study has demonstrated that the tumoricidal bystander effect does not injure the background normal brain tissue significantly and that the suicide gene therapies are sufficiently safe.

Migration of mouse-induced pluripotent stem cells to glioma-conditioned medium is mediated by tumor-associated specific growth factors.

Neural and mesenchymal stem cells have extensive tropism for malignant glioma. The tumor tropism of induced pluripotent stem (iPS) cells was tested using the Matrigel invasion assay. Mouse iPS cells showed a significant tropism to the conditioned media prepared from six rodent and human glioma cell lines and this tropism to the glioma conditioned media was partially blocked by the neutralizing antibodies for four major tumor-associated growth factors [stem cell factor (SCF), platelet-derived growth factor BB (PDGF-BB), stromal-derived factor-1α (SDF-1α) and vascular endothelial growth factor (VEGF)], which are secreted from the malignant gliomas. The tropism of the iPS cells was enhanced by the growth factors in a concentration-dependent manner from 0.1 to 100 ng/ml. The receptors for those growth factors (c-Kit, ICAM-1, CXCR4 and VEGFR2), measured by reverse transcriptase-polymerase chain reaction, were highly up-regulated in the mouse iPS cells compared to the mouse fibroblasts. The results showed that the specific growth factors secreted from the gliomas strongly attracted the iPS cells. Therefore, gene therapies using iPS cells as vectors to deliver anti-tumor agents are novel strategies for the treatment of malignant gliomas that deeply infiltrate the brain.