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Background: Endoscopic third ventriculostomy (ETV) for obstructive hydrocephalus and endoscopic biopsy (EB) for intraventricular and paraventricular tumors are standard therapies because they are minimally invasive procedures. Although EB-associated hemorrhagic risk has been well documented, there have been only a few reports on hemorrhagic risk associated with ETV. We conducted a single-institution retrospective study on the incidence of hemorrhage secondary to EB and/or ETV., Methods: We retrospectively reviewed patient characteristics, procedure, pathological findings, and complications including hemorrhage of 100 patients with intraventricular and paraventricular tumors who underwent EB and/or ETV at our institution from 2000 to 2020., Results: EB/ETV combined surgery (combined group), EB-alone surgery (EB-alone group), and ETV-alone surgery (ETV-alone group) were performed in 44 (44%), 24 (24%), and 32 (32%) patients, respectively, and all procedures were successful. The rates of definitive and suggestive diagnoses in EB were 76.5% and 23.5%, respectively. Adverse events were observed in 6 patients. In the combined group, acute obstruction of the ETV stoma was observed in 1 patient and transient double vision was observed in 1 patient. Transient aqueductal stenosis/obstruction was observed in 2 patients in the EB-alone group. In the ETV-alone group, hemorrhage was observed in 2 patients; these patients developed intratumoral hemorrhage despite ETV-alone surgery. Subsequently, these 2 patients underwent tumor removal, and the histopathological diagnosis was atypical teratoid/rhabdoid tumor in both., Conclusions: For obstructive hydrocephalus with atypical teratoid/rhabdoid tumor, physicians must be aware of the risk of postoperative intratumoral hemorrhage after performing ETV., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Posterior fossa ependymoma (PF-EPN) was categorized into PF-EPN-A and PF-EPN-B subgroups based on the DNA methylation profiling. PF-EPN-A was reported to have poorer prognosis compared with PF-EPN-B. In this study, we particularly evaluated preoperative imaging to distinguish PF-EPN-A from PF-EPN-B., Methods: Sixteen cases of PF-EPN were treated in our institution from 1999 to 2018. The patients were divided into PF-EPN-A and PF-EPN-B groups based on H3K27me3 immunostaining positivity. We evaluated progression-free survival, overall survival, as well as preoperative magnetic resonance imaging and computed tomography scan images in both groups. Based on T1WI and Gd-T1WI magnetic resonance images, the tumor contrast rate was determined from dividing the volume of gadolinium enhanced tumor by the overall tumor volume., Results: Nine cases (4 male, 5 female) were grouped as PF-EPN-A, and 7 (4 male, 3 female) as PF-EPN-B. The median age of PF-EPN-A and PF-EPN-B were 4 and 43 years old, respectively. In the PF-EPN-A group, the progression-free survival median value was 32.6 months, and the overall survival median was 96.9 months. In contrast, PFS in PF-EPN-B did not reach a median value (P < 0.05) and all the patients were alive (P < 0.05) at the end of the study. With imaging, tumor contrast rate in PF-EPN-B was more than 50% and significantly different from PF-EPN-A (P = 0.0294). Calcification was mainly observed in PF-EPN-A, whereas cystic formation was only seen in PF-EPN-B., Conclusions: Contrast rate less than 50%, based on the magnetic resonance images, was characteristic in the PF-EPN-A group. Comparatively, cystic component and absence of calcification were more characteristic in the PF-EPN-B group., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The term "growing teratoma syndrome (GTS)" has been used as follows: patients with germ cell tumor (GCT) who present with enlarging original/metastatic masses during or after appropriate systemic chemotherapy despite normalized serum markers. In other words, the definition of the term GTS is not fully established. We analyzed and reviewed our case series regarding GTS that developed after the treatment of central nervous system (CNS) nongerminoatous germ cell tumors (NGGCTs)., Methods: Our institutional review board approved this retrospective study. Between 2003 and 2018, we treated 16 patients (16 males; age ranging from 5.4 to 51.9 years, median 13.8) with CNS-NGGCT at our institution. We reviewed those patients and also reviewed the literature about GTS of CNS. We defined primary GTS (p-GTS) as the enlargement of cyst size and/or solid tumor occurred during treatment in the absence of marker elevation, and recurrent GTS (r-GTS) as the enlargement of teratoma after complete response of initial tumors., Results: Among 16 patients with CNS-NGGCT, we surgically confirmed mature/immature teratoma components in 15 patients. Two patients underwent surgical removal of tumor before neoadjuvant therapy, and among the rest 14 patients, 6 developed p-GTS, and 2 patients underwent salvage surgery during chemo-/chemoradiotherapy. Those with histologic diagnosis of immature teratoma during salvage surgery had a shorter interval from the initiation of chemoradiotherapy compared with mature teratoma (P < 0.05). One patient developed r-GTS. In the literature review, most of the p-GTS consisted of enlargement with the multicystic component. Histologic diagnosis of immature teratoma during salvage surgery was observed in earlier stages of chemoradiotherapy (P < 0.05, log-rank test). Previous history of p-GTS might be a risk factor of r-GTS., Conclusions: The incidence of p-GTS, enlargement of the cystic component during treatment, is not rare. Physicians need to be aware of this important phenomenon., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Several intracranial pathologies present as a ring-enhancing lesion on conventional magnetic resonance imaging (MRI), creating diagnostic difficulty. We studied the characteristics of the anatomical border of gadolinium enhancement on T1-weighted imaging (WI) and hypointensity on T2WI to employ a simple technique of histogram-profile analysis of MRI for differentiation of various ring-enhancing intracranial lesions., Methods: After approval from the institutional review board, preoperative MRI (T2WI, postcontrast T1WI) scans were analyzed retrospectively in 18 patients with histologically confirmed brain abscess, 66 glioblastomas, 46 brain-metastases, and 16 tumefactive multiple sclerosis (MS). T2WI and postcontrast T1WI were overlapped, and histogram-profile analysis was performed with in-house image-fusion software. The pattern of differential-peaks in histogram-profile was assessed visually. Kaplan-Meier survival analysis incorporating histogram-profile patterns was performed in patients with glioblastoma., Results: The histogram-profile study revealed 4 distinct patterns. Pattern 1 showed no differential T2-hypointensity trough, pattern 2 had T2-hypointensity trough inside, whereas pattern 3 had T2-hypointensity trough overlapping the enhanced margin. Pattern 4 had T2-hypointensity trough immediately external to the enhanced margin. Pattern 1 was specific for tumefactive MS (93.3%), whereas pattern 4 was specific for glioblastoma (40.7%). Pattern 4 glioblastoma was subdivided into rim (T2-hypointensity ≥50% of circumference of contrast-enhanced tumor) and arc (T2-hypointensity <50% of circumference of contrast-enhanced tumor). Pattern 4 glioblastoma was further subdivided into group A (edema: T2-hyperintensity ≥50% of circumference of contrast-enhanced tumor) and group B (less edema: T2-hyperintensity <50% of circumference of contrast-enhanced tumor). Patients with pattern 3 glioblastoma (37.6%) had better survival compared with others (P = 0.0341) and pattern 4B had decreased survival compared with pattern 4A (P = 0.0001) and others (P = 0.0003)., Conclusions: Tumefactive MS and a subset of glioblastomas show specific patterns in histogram-profile analysis. The difference in anatomical border also determines difference in survival in glioblastoma. Histogram-profile analysis is a simple and efficient technique to differentiate these pathologies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Evaluation of plaque protrusion after carotid artery stenting (CAS) is important for predicting periprocedural ischemic complications. In contrast to intravascular ultrasound (IVUS), angioscopy allows direct visualization of the plaque. The aim of this study was to evaluate utility and safety of angioscopy during CAS and compare it with IVUS., Methods: The study included 13 carotid artery stenosis lesions in 11 consecutive patients (mean age 70.5 years; 10 men) at a single center. During CAS procedure, poststenting plaque protrusion was evaluated with angioscopy and IVUS., Results: Mean level of internal carotid artery stenosis was 79.2%. Eight lesions were symptomatic, and 5 lesions were predicted to have vulnerable plaque by preprocedural magnetic resonance imaging. A carotid WALLSTENT was placed in all cases. After stenting, angioscopy provided good visualization in all cases. Plaque protrusions were observed in 1 case by IVUS and in 8 cases by angioscopy. Diffusion-weighted imaging showed positive lesions in 3 cases (23%). For 2 of these lesions, plaque protrusions were observed by angioscopy but not by IVUS. All lesions associated with positive diffusion-weighted imaging findings were observed to have yellow plaque on angioscopy., Conclusions: Angioscopy provided direct visualization of stent lumens after CAS. Angioscopy detected more plaque protrusion than IVUS and allowed clearer observation of plaque characteristics. Angioscopy may be more useful than IVUS for examination of plaque protrusion and plaque evaluation after CAS, especially for plaque identified as potentially vulnerable by preprocedural examination., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Perfusion computed tomography (PCT) reflects blood flow and capillary condition, which is valuable in assessing brain tumors. We evaluated PCT parameters at the tumor (t) and peritumoral (p) region to differentiate malignant brain tumors., Methods: We performed PCT in 39 patients with supratentorial malignant brain tumors (22 glioblastomas, 6 lymphomas, 11 metastases). Regions of interests were placed manually at tumor, peritumoral region, and contralateral normal-appearing white matter. Cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and permeability surface (PS) were measured. These parameters were divided by those of contralateral normal-appearing white matter to normalize at tumor (relative [r]CBVt, rCBFt, rMTTt, rPSt) and peritumoral regions (rCBVp, rCBFp, rMTTp, rPSp). The parameters were evaluated with Mann-Whitney U test and receiver operating characteristics analyses. Stepwise analyses also were performed to select useful PCT parameters for differentiating these tumors., Results: The rCBFt and rCBVt of glioblastoma (GBM) were greater than those of primary central nervous system lymphoma (PCNSL) (P = 0.0005, 0.0002) and brain metastasis (METS) (P = 0.0044, 0.0028). The rMTTp of METS was greater than that of GBM and PCNSL (P = 0.0001, 0.0007). The combination of rCBVt and rPSt could differentiate GBM from other tumors with sensitivity and specificity of 81.8% and 94.1%. The combination of rCBFp and rMTTp could differentiate METS from other tumors with sensitivity and specificity of 90.9% and 82.1%., Conclusions: Our study introduces and supports the usefulness of PCT parameters for differentiation among GBM, PCNSL, and METS. rCBVt and rPSt may be the best predictors of GBM. rCBFp and rMTTp may be the best predictors of METS., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: The differentiation of germinoma from other tumors by conventional magnetic resonance imaging (MRI) can be very difficult. The purpose of our study was to determine whether diffusion-weighted imaging (DWI) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) could provide additional useful information for a definitive diagnosis of germinomas., Methods: Our hospital's Institutional Review Board approved this retrospective study. We reviewed imaging studies of 26 patients with histologically confirmed germinomas who were treated at our hospital between 2003 and 2016. We also studied 25 patients with pineal tumors, which included 14 nongerminomatous germ cell tumors (NGGCTs), 9 pineal parenchymal tumors (PPTs; including 3 pineocytomas, 4 PPTs of intermediate differentiation [PPTID], and 2 pineoblastomas) and 2 meningiomas. Patients underwent conventional MRI and advanced MRI, including DWI and/or 1H-MRS., Results: The germinoma group comprised 24 males and 2 females, ranging in age from 9.1 to 37.7 years (average, 17.5 years; median, 14.6 years). The NGGCT group was all male, ranging in age from 5.4 to 51.9 years (mean, 20.1 years; median, 14.1 years). In the PPT group, patient age ranged from 4.5 to 64.7 years (mean, 29.9 years; median, 30.7 years). High lipid peaks detected on 1H-MRS were observed in 16 of 16 examined germinomas. In contrast, in the pineocytomas, PPTID, pineoblastomas, and meningiomas, lipid peaks were small or absent in 10 of 10 examined tumors. In the NGGCT group, high lipid peaks on 1H-MRS were observed in 11 of 12 examined tumors; however, no tumors showed high intensity on DWI, with all low to high mixed intensity. ADC was statistically lower in the germinoma group compared with the NGGCT group (P = 0.0002)., Conclusions: Lower ADC values and high lipid peaks detected on 1H-MRS are characteristics of germinomas., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: A neuroendoscopic biopsy has become common for the diagnosis of ventricular tumors. However, its utility in patients with germ cell tumors (GCTs) has not been well discussed. We examined the usefulness and pitfalls of neuroendoscopic biopsies of intraventricular GCTs at a single institution., Methods: We retrospectively studied 21 consecutive patients diagnosed with GCTs by a neuroendoscopic biopsy of the ventricular region via the lateral ventricle. We examined the localization of tumors, histologic diagnoses using biopsies, surgical complications, and consistency of the diagnosis at the latest follow-up., Results: Tumor specimens were obtained from a pineal lesion (n = 20), neurohypophysial lesion (n = 5), and lateral ventricular wall lesion (n = 2). In 5 patients, the specimens were obtained from multiple areas. The initial diagnoses were pure germinoma (n = 16), immature teratoma (n = 1), yolk sac tumor (n = 1), and mixed GCT (n = 3). Six of 21 patients needed a second transcranial removal of enhanced residual lesions in the course of the treatment. A discrepancy in the histologic diagnosis between 2 surgeries occurred in 3 patients: All 3 patients had a new diagnosis of teratoma component following transcranial surgery. No postoperative mortality or permanent morbidity related to the neuroendoscopic procedures was noted., Conclusion: Neuroendoscopic biopsies are safe and useful for obtaining reliable histologic diagnoses in the management of GCTs. However, for GCTs with mixed histology, biopsies are susceptible to diagnostic errors, especially missing detecting a component of teratoma., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: Glioblastoma (GBM) relapses locally or in a disseminated pattern and is highly resistant to chemoradiotherapy. Although dissemination is associated with poor prognosis for patients with GBM, the clinicopathologic factors that promote dissemination have not been elucidated. Glypican-1 (GPC-1) is a heparin sulfate proteoglycan that is attached to the extracytoplasmic surface of the cell membrane and regulates cell motility. The aim of this study was to determine whether GPC-1 expression correlated with GBM dissemination and patient prognosis., Methods: GPC-1 expression was examined by immunohistochemistry in 53 patients with GBM who received radiotherapy and temozolomide treatment. We assessed the relationship between dissemination and clinicopathologic factors, including GPC-1 expression. We also evaluated the relationship between GPC-1 expression and overall survival (OS) by uni- and multivariate analyses of a range of clinicopathologic factors, including age, Karnofsky Performance Status, extent of resection, and O6-methylguanine-DNA methyltransferase (MGMT) status., Results: Logistic regression analysis revealed that GPC-1 expression correlated with dissemination (P = 0.0116). Log-rank tests revealed that age, Karnofsky Performance Status, extent of resection, MGMT status, dissemination (P = 0.0008) and GPC-1 expression (P = 0.0011) were significantly correlated with OS. Multivariate analysis indicated that age, MGMT status, and GPC-1 expression were significantly correlated with OS. GPC-1 expression had the highest hazard ratio (2.392) among all regressors., Conclusions: GPC-1 expression significantly correlated with OS in patients with GBM who received radiotherapy and temozolomide treatment. GPC-1 expression can help predict the occurrence of dissemination and shorter OS in patients with GBM., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: It is sometimes difficult to make a differential diagnosis between brain metastases and hemangioblastomas in the posterior fossa. We assessed whether high b value diffusion-weighted image (DWI) at b = 4000 could differentiate these tumors., Methods: We acquired DWI at 3-T magnetic resonance imaging with b = 1000 and b = 4000 seconds/mm 2 in histologically confirmed 12 patients of hemangioblastoma without von Hippel-Lindau disease and 16 patients with brain metastases originating at the posterior fossa. Apparent diffusion coefficient (ADC) values were measured by manually placing regions of interest on ADC maps at the site of enhanced tumor confirmed on contrast-enhanced T1- weighed image. ADC was expressed as the minimum (ADC MIN ), mean (ADC MEAN ), and maximum (ADC MAX ) values., Results: All the ADC values of hemangioblastomas were statistically higher than those of metastatic tumor in both b = 1000 and b = 4000 (P < 0.0001 in ADC MIN , ADC MEAN , and ADC MAX ; Mann-Whitney U test). With the cutoff value at 0.6 × 10 -3 mm 2 /second, the positive predictive value of ADC MIN at b = 4000 was higher than that of ADC MIN at b = 1000 (100% vs. 89.3%, logistic analysis) to differentiate hemangioblastomas from brain metastases. Moreover, we studied the pathologic subtype of hemangioblastoma and confirmed that ADCs (b = 4000 MIN ) of cellular subtype were statistically lower than those of reticular subtype (P = 0.03; Mann-Whitney U test)., Conclusions: High b value DWI reflects diffusion more accurately than does regular b value. Our results showed that ADC calculation by high b value (b = 4000) DWI at 3-T magnetic resonance imaging is clinically useful for differentiating hemangioblastomas from brain metastases., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: The differential diagnosis of neurohypophysial lesions is difficult, and surgical biopsies are indispensable in the histologic diagnosis of some patients. Although pituitary stalk biopsies are uniformly performed, there is a considerable risk that they will result in impaired hormonal secretion. We attempt to clarify the usefulness and safety of posterior pituitary lobe biopsy by transsphenoidal surgery (TSS)., Methods: The cases of 11 consecutive patients who underwent posterior pituitary lobe biopsies by TSS were retrospectively studied. Patients with cystic sellar lesions were excluded. We examined the clinical findings, endocrinologic data, magnetic resonance imaging findings, and histologic diagnoses of the patients. The locations of neurohypophysial lesions and the histologic diagnoses by posterior pituitary lobe biopsies were examined., Results: The major preoperative clinical symptoms were diabetes insipidus (DI) (90.9%), followed by anterior pituitary lobe dysfunction (hypopituitarism) (54.5%). In all the patients, the lesions occupied the pituitary stalk and the posterior pituitary lobe, and the bright spot, which would indicate a normal posterior pituitary gland, disappeared on T1-weighted imaging. The posterior pituitary lobe specimens could be histologically diagnosed in all these cases. DI persisted in 10 patients with preoperative DI after the biopsy, whereas the 1 patient without preoperative DI did not suffer from DI after the biopsy., Conclusions: A posterior pituitary lobe biopsy by TSS may be an alternative to pituitary stalk biopsy in patients with neurohypophysial lesions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: The current standard treatment protocol for patients with newly diagnosed glioblastoma (GBM) includes surgery, radiotherapy, and concomitant and adjuvant temozolomide (TMZ). We hypothesized that the permeability surface area product (PS) from a perfusion computed tomography (PCT) study is associated with sensitivity to TMZ. The aim of this study was to determine whether PS values were correlated with prognosis of GBM patients who received the standard treatment protocol., Methods: This study included 36 patients with GBM that were newly diagnosed between October 2005 and September 2014 and who underwent preoperative PCT study and the standard treatment protocol. We measured the maximum value of relative cerebral blood volume (rCBVmax) and the maximum PS value (PSmax). We statistically examined the relationship between PSmax and prognosis using survival analysis, including other clinicopathologic factors (age, Karnofsky performance status [KPS], extent of resection, O6-methylguanine-DNA methyltransferase [MGMT] status, second-line use of bevacizumab, and rCBVmax)., Results: Log-rank tests revealed that age, KPS, MGMT status, and PSmax were significantly correlated with overall survival. Multivariate analysis using the Cox regression model showed that PSmax was the most significant prognostic factor. Receiver operating characteristic curve analysis showed that PSmax had the highest accuracy in differentiating longtime survivors (LTSs) (surviving more than 2 years) from non-LTSs. At a cutoff point of 8.26 mL/100 g/min, sensitivity and specificity were 90% and 70%, respectively., Conclusions: PSmax from PCT study can help predict survival time in patients with GBM receiving the standard treatment protocol. Survival may be related to sensitivity to TMZ., (Copyright © 2016 Elsevier Inc. All rights reserved.)