Pre- and post-operative semicircular canal function evaluated by video head impulse test in patients with vestibular schwannoma

OBJECTIVES

To evaluate pre- and post-operative semicircular canal function in patients with vestibular schwannoma (VS) by the video Head Impulse Test (vHIT).

METHODS

Nineteen patients with VS who underwent surgery were enrolled in this study. The gain in vestibulo-ocular reflex (VOR) and the degree of scatter in catch-up saccades were examined pre- and post-operatively for the semicircular canals in VS patients.

RESULTS

Ten of 19 cases (52.6 %) with VS were defined as demonstrating both superior vestibular nerve (SVN) and inferior vestibular nerve (IVN) impairment from the results of pre-operative vHIT. Hearing level and subjective vestibular symptoms showed significant correlations with pre-operative semicircular canal function. Compared to pre-operative vHIT results, VOR gains within 1 month after surgery were significantly reduced in all three canals; however, significant differences had disappeared in the anterior and posterior semicircular canals at 6 months after surgery. Cases of unknown origin had a significantly greater reduction in posterior semicircular canal function after surgery compared with those with disease of IVN origin.

CONCLUSIONS

As vHIT could evaluate pre-operative vestibular nerve impairment, post-operative VOR gain reduction and the degree of vestibular compensation, semicircular canal function evaluated by vHIT provides a good deal of useful information regarding VS patients undergoing surgery compared to caloric testing, and vHIT should be performed pre- and post-operatively for patients with VS.

Clinical outcomes for olfactory neuroblastoma

Background

Olfactory neuroblastoma (ONB) is a rare malignant tumor arising from the olfactory neuroepithelium. The standard of care for ONB is surgical resection; however, detailed treatment protocols vary by institution. Our treatment protocol consists of endoscopic skull base surgery (ESBS) for endoscopically resectable cases and induction chemotherapy followed by craniotomy combined with ESBS for locally advanced cases, with postoperative radiotherapy performed for all cases. Chemoradiotherapy (CRT) is performed in unresectable cases. In this study, we evaluate our treatment protocol and outcomes for ONB.

Methods

A retrospective review of patients with ONB was conducted. Outcomes included survival outcomes and perioperative data.

Results

Fifteen patients (53.6%) underwent ESBS, 12 (42.9%) underwent craniotomy combined with ESBS, and 1 (3.6%) received CRT. The 5- and 10-year overall survival rates for all patients were 92.9% and 82.5%, respectively, with a median follow-up period of 81 months. The 5- and 10-year disease-free survival rates were 77.3% and 70.3%, respectively, and the 5- and 10-year local control rates were 88.2% and 80.2%, respectively. Patients undergoing ESBS demonstrated a significantly shorter operating time, period from operation to ambulation, hospitalization period, and less blood loss than those undergoing craniotomy combined with ESBS.

Conclusion

Our treatment protocol was found to afford favorable outcomes. Patients who underwent endoscopic resection showed lower complication rates and better perioperative data than those who underwent craniotomy combined with ESBS. With appropriate case selection, ESBS is considered a useful approach for ONB.

Identifying G6PC3 as a Potential Key Molecule in Hypoxic Glucose Metabolism of Glioblastoma Derived from the Depiction of 18F-Fluoromisonidazole and 18F-Fluorodeoxyglucose Positron Emission Tomography

Purpose

Glioblastoma is the most aggressive primary brain tumor, characterized by its distinctive intratumoral hypoxia. Sequential preoperative examinations using fluorine-18-fluoromisonidazole (18F-FMISO) and fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) could depict the degree of glucose metabolism with hypoxic condition. However, molecular mechanism of glucose metabolism under hypoxia in glioblastoma has been unclear. The aim of this study was to identify the key molecules of hypoxic glucose metabolism.

Methods

Using surgically obtained specimens, gene expressions associated with glucose metabolism were analyzed in patients with glioblastoma (n = 33) who underwent preoperative 18F-FMISO and 18F-FDG PET to identify affected molecules according to hypoxic condition. Tumor in vivo metabolic activities were semiquantitatively evaluated by lesion-normal tissue ratio (LNR). Protein expression was confirmed by immunofluorescence staining. To evaluate prognostic value, relationship between gene expression and overall survival was explored in another independent nonoverlapping clinical cohort (n = 17) and validated by The Cancer Genome Atlas (TCGA) database (n = 167).

Results

Among the genes involving glucose metabolic pathway, mRNA expression of glucose-6-phosphatase 3 (G6PC3) correlated with 18F-FDG LNR (P = 0.03). In addition, G6PC3 mRNA expression in 18F-FMISO high-accumulated glioblastomas was significantly higher than that in 18F-FMISO low-accumulated glioblastomas (P < 0.01). Protein expression of G6PC3 was consistent with mRNA expression, which was confirmed by immunofluorescence analysis. These findings indicated that the G6PC3 expression might be facilitated by hypoxic condition in glioblastomas. Next, we investigated the clinical relevance of G6PC3 in terms of prognosis. Among the glioblastoma patients who received gross total resection, mRNA expressions of G6PC3 in the patients with poor prognosis (less than 1-year survival) were significantly higher than that in the patients who survive more than 3 years. Moreover, high mRNA expression of G6PC3 was associated with poor overall survival in glioblastoma, as validated by TCGA database.

Conclusion

G6PC3 was affluently expressed in glioblastoma tissues with coincidentally high 18F-FDG and 18F-FMISO accumulation. Further, it might work as a prognostic biomarker of glioblastoma. Therefore, G6PC3 is a potential key molecule of glucose metabolism under hypoxia in glioblastoma.

Increased CD44 expression in primary meningioma: its clinical significance and association with peritumoral brain edema

OBJECTIVE

CD44 is a major cell surface receptor involved in cell adhesion and migration. The overexpression of CD44 is a poor prognostic factor in many neoplasms, including meningiomas. The aim of this study was to investigate the association between CD44 gene expression and clinical signatures of primary meningiomas.

METHODS

CD44 gene expression was quantitatively evaluated by snap freezing tumor tissues obtained from 106 patients with primary meningioma. The relationships between CD44 expression and clinical signatures of meningiomas, including histological malignancy, tumor volume, and peritumoral brain edema (PTBE), were analyzed. PTBE was assessed using the Steinhoff classification (SC) system (from SC 0 to SC III).

RESULTS

CD44 gene expression in WHO grade 2 and 3 meningiomas was significantly higher than that in grade 1 meningiomas. In addition, CD44 expression increased with the severity of PTBE. Particularly, among the grade 1 meningiomas or small-sized tumors (maximum tumor diameter < 43 mm), CD44 expression in tumors with severe PTBE (SC II or III) was significantly higher than that in tumors without or with mild PTBE (SC 0 or I). Multivariate logistic regression analysis also revealed that overexpression of CD44 was an independent significant factor of severe PTBE development in primary meningiomas.

CONCLUSIONS

In addition to tumor cell aggressiveness, CD44 expression promotes the development of PTBE in meningioma. Since PTBE is a strong factor of tumor-related epilepsy or cognitive dysfunction in patients with meningioma, CD44 is thus a potential therapeutic target in meningioma with PTBE.

Supratentorial multifocal gliomas associated with Ollier disease harboring IDH1 R132H mutation: A case report

Somatic mosaicism of isocitrate dehydrogenase 1/2 (IDH1/2) mutation is a cause of Ollier disease (OD), characterized by multiple enchondromatosis. A 35-year-old woman who was diagnosed with OD at age 24 underwent resection surgery for multifocal tumors located at the right and left frontal lobes that were discovered incidentally. No apparent spatial connection was observed on preoperative magnetic resonance imaging. Pathological examinations revealed tumor cells with a perinuclear halo in the left frontal lobe tumor, whereas astrocytic tumor cells were observed in the right frontal lobe tumor. Based on positive IDH1 R132H immunostaining and the result of 1p/19q fluorescent in situ hybridization, pathological diagnoses were IDH mutant and 1p/19q-codeleted oligodendroglioma in the right frontal lobe tumor and IDH mutant astrocytoma in the left frontal lobe tumor, respectively. The DNA sequencing revealed IDH1 R132H mutation in the peripheral blood sample and frontal lobe tumors. This case suggested that in patients with OD, astrocytoma and oligodendroglioma can co-occur within the same individual simultaneously, and IDH1 R132H mutation was associated with supratentorial development of gliomas.

Neuromedin B receptor as a potential therapeutic target for corticotroph adenomas

PURPOSE

Cushing's disease (CD) results from autonomous adrenocorticotropic hormone (ACTH) secretion by corticotroph adenomas, leading to excessive cortisol production, ultimately affecting morbidity and mortality. Pasireotide is the only FDA approved tumor directed treatment for CD, but it is effective in only about 25% of patients, and is associated with a high rate of hyperglycemia. Neuromedin B (NMB), a member of the bombesin-like peptide family, regulates endocrine secretion and cell proliferation. Here, we assessed NMB and NMB receptor (NMBR) expression in human corticotroph adenomas and the effects of NMBR antagonist PD168368 on murine and human corticotroph tumors.

METHODS

To investigate NMB and NMBR expression, real-time qPCR and immunostaining on human pathological specimens of corticotroph, non-functional and somatotroph adenomas were performed. The effects of PD168368 on hormone secretion and cell proliferation were studied in vitro, in vivo and in seven patient-derived corticotroph adenoma cells. NMB and NMBR were expressed in higher extent in human corticotroph adenomas compared with non-functional or somatotroph adenomas.

RESULTS

In murine AtT-20 cells, PD168368 reduced proopiomelanocortin (Pomc) mRNA/protein expression and ACTH secretion as well as cell proliferation. In mice with tumor xenografts, tumor growth, ACTH and corticosterone were downregulated by PD168368. In patient-derived adenoma cells, PD168368 reduced POMC mRNA expression in four out of seven cases and ACTH secretion in two out of five cases. A PD168368-mediated cyclin E suppression was also identified in AtT-20 and patient-derived cells.

CONCLUSION

NMBR antagonist represents a potential treatment for CD and its effect may be mediated by cyclin E suppression.

Quantitative Evaluations of Vestibular Function in Patients With Petrous Apex Cholesterol Granulomas Treated With an Endoscopic Transsphenoidal Approach: A Report of Two Cases

OBJECTIVE

We report two cases of petrous apex cholesterol granuloma (PACG) treated with an endoscopic transsphenoidal approach. Vestibular functions of the two patients were evaluated quantitatively by video Head Impulse Test (vHIT) and/or vestibular evoked myogenic potentials (VEMPs).

PATIENTS

Two patients with PACG who experienced episodes of dizziness are presented.

INTERVENTION

An endoscopic transsphenoidal approach to PACG.

MAIN OUTCOME MEASURE

The preoperative and postoperative vestibular functions as evaluated by vHIT and VEMP.

RESULTS

Two cases of PACG were treated by a transsphenoidal approach. The internal auditory canal was compressed by the PACG in both cases. The patients both experienced episodes of dizziness before surgery and preoperative vestibular testing including vHIT and VEMP indicated dysfunction of vestibular nerves. After surgery, their symptoms were completely resolved, and the vestibular testing results were improved.

CONCLUSIONS

This article is noteworthy for being the first to publish quantitative vestibular function testing for patients with PACG with vestibular dysfunction. PACG may show various symptoms, with dizziness being one of the most common symptoms. In cases in which the internal auditory canal is compressed by the PACG, vestibular functions should be evaluated by vHIT and VEMP. In the present cases, dizziness was found to be resolved by surgery to release the compression on internal auditory canal. Based on the present cases, the transsphenoidal approach is considered to be both safe and effective.

Slow-growing WNT medulloblastoma with atypical magnetic resonance imaging findings: illustrative case

BACKGROUND

Medulloblastomas, with four molecular subgroups, are generally rapid-growing tumors with significant contrast enhancement and well-defined margins. However, each subgroup's clinical features, including disease time course and imaging characteristics, are not well defined.

OBSERVATIONS

The authors describe the case of a 15-year-old female who presented with a 7-month history of impaired left-hand movement and was found to have a lesion on the dorsal side of the fourth ventricle. T2-weighted magnetic resonance imaging (MRI) at the patient's first presentation showed diffuse hyperintense signal without apparent mass, and gadolinium-enhanced T1-weighted imaging showed very slight contrast enhancement. In 1 month, her symptoms progressed, and follow-up MRI revealed an increase in the size of the lesion, showing greater diffusion restriction and contrast enhancement. She underwent gross-total resection, and pathology was consistent with classic medulloblastoma. Genetic analysis of the tumor confirmed the wingless (WNT) molecular subgroup. Adjuvant chemotherapy and proton beam therapy were performed. At the 18-month follow-up, MRI showed no recurrence of disease.

LESSONS

Slow-growing medulloblastoma is very rare and not known to be associated with a specific molecular subgroup. Here, the authors report a case of slow-growing WNT medulloblastoma, indicating that slow growth may be a feature of this subgroup.

ODP338 Neuromedin B Receptor Antagonist Suppresses ACTH Secretion and Cell Proliferation in Human and Mouse Corticotroph Adenoma

Objective

We previously reported that Neuromedin B (NMB) is expressed in murine pituitary corticotrophs under adrenal insufficiency (1). Because NMB is also expressed in several cancer cells and stimulates ACTH secretion, we hypothesized that NMB is related to corticotroph adenoma cell proliferation and hormone secretion. To examine this hypothesis, we investigated the effects of a NMB receptor (NMBR) antagonist on AtT-20 cells, a tumor xenograft model and patient-derived corticotroph adenoma cells.

Methods

1. NMB and NMBR expression in human pituitary adenoma: We performed real-time qPCR and immunostaining on human pathological specimens of corticotroph and non-functioning pituitary adenomas to investigate NMB and NMBR expression. 2. Experiments in AtT-20 cells: We extracted RNAs, proteins and mediums from AtT-20 cells after incubation with NMBR antagonist PD168368, and performed real-time qPCR, western blotting and ELISA analyses. We also performed WST-1 assay to investigate cell proliferation. 3. Experiments in a tumor xenograft model: AtT-20 cells in Matrigel were injected subcutaneously into BALB/c-nu mice. A week after inoculation, we administered 1.2 mg/kg PD168368 intraperitoneally once daily for 14 days. Upon completion of treatment, tumors were measured and cardiac blood was collected. 4. Experiments in patient-derived corticotroph adenoma cells: We isolated surgically resected human corticotroph adenoma cells from patients who underwent trans-sphenoidal surgery and investigated mRNA expression and medium ACTH secretion after incubation with PD168368. Statistical analysis: Comparisons between two groups were made by unpaired Student t test. Multiple groups were compared using one-way ANOVA followed by Dunnett's test for comparison with control group. Statistical significance was defined as p < 0. 05.

Results

1. NMB and NMBR expression levels were significantly higher in human corticotroph adenomas (13 and 33 times higher, respectively) than in non-functioning adenomas in the qPCR analyses. Immunostaining confirmed higher expression of NMB and NMBR in corticotroph adenoma. 2. Treatment with 100 nM PD168368 significantly suppressed Pomc mRNA and protein expression in AtT-20 cells by 22% and 25% respectively compared control group. Medium ACTH secretion, mRNA and protein expression of cyclin E1 and cell proliferation were also suppressed by PD168368. 3. Mice treated with PD168368 had significantly lower tumor growth rate, plasma ACTH and corticosterone than control group (70 vs 161%, 97 vs 180 pg/ml, 813 vs 1045 ng/ml, respectively). 4. Treatment with PD168368 significantly suppressed POMC mRNA expression (12-31%) in 4 out of 6 patient-derived corticotroph adenoma cells. Medium ACTH secretion was also suppressed (14-53%) in 3 out of 4 cases which could be evaluated. Cyclin E mRNA expression were also suppressed in 3 out of 4 cases in which POMC mRNA expression were suppressed.

Conclusions

NMBR antagonist may represent a potential treatment for Cushing disease, which effect may be mediated by decreased cyclin E expression. Reference: (1) Kameda H et al., Endocrinology 2014;155(7): 2492–9.

Presentation: No date and time listed

Long-term consequences of residual lesions after chemoradiotherapy in patients with germinoma at onset

OBJECTIVE

In patients with intracranial germ cell tumors, residual lesions are sometimes observed after completion of primary chemoradiotherapy. Although salvage resection of these end-of-treatment residual lesions is recommended for patients with nongerminomatous germ cell tumors, the necessity of early salvage resection for those with germinoma is not clear. The aim of this study was to investigate the frequency of residual germinoma lesions after primary chemoradiotherapy, as well as their management, long-term consequences, and prognosis.

METHODS

The authors retrospectively reviewed patients who were primarily treated for germinoma between 2002 and 2021. Residual lesions were evaluated with MRI with and without contrast enhancement within 2 weeks after chemoradiotherapy. The decision to perform salvage resection of residual lesions was at the discretion of the treating physicians. The change in appearance of residual lesions was assessed with serial MRI. Overall survival (OS), progression-free survival (PFS), and recurrence pattern were also investigated.

RESULTS

Sixty-nine patients were treated with chemoradiotherapy for germinoma, with a mean follow-up period of 108 months. Residual lesions were radiologically observed in 30 patients (43.5%). Among these, 5 patients (3 with pineal lesions and 2 with basal ganglia lesions) underwent salvage resection. Pathological examination revealed teratomatous components in 3 patients, whereas no tumoral components were identified in 2 patients. One patient with a basal ganglia lesion showed worsening of hemiparesis postoperatively. The remaining 25 patients received watchful observation without surgical intervention. Chronological periodic radiological change in residual lesions was evaluated in 21 patients. One year after primary treatment, the size of the residual lesions was stable and had decreased in 10 and 11 patients, respectively. None of the lesions increased in size. The 10-year PFS and OS rates were 96.7% and 97.3% in patients without residual lesions (n = 39), and 87.1% and 100% in patients with residual lesions (n = 30), respectively. Presence of residual lesions had no significant effect on PFS or OS. All recurrences occurred at distant sites or via dissemination without progression of the primary tumor site, regardless of the presence of residual lesion.

CONCLUSIONS

End-of-treatment residual lesions are not rare in patients with germinoma, and these residual lesions seldom show progression. Because of the potential risk of surgical complications, the indication for early salvage surgery for residual lesions should be carefully determined. Watchful observation is recommended for the majority of these cases.

ODP328 Longitudinal Multidisciplinary Approach for Cabergoline-Resistant Aggressive Prolactinoma Complicated by Multiple Endocrine Neoplasia Type 1

Background

Cabergoline-resistant prolactinomas comprise approximately 10% of all prolactinomas, and sometimes show aggressive features including invasion or higher proliferation profiles. The treatment for such cabergoline-resistant aggressive prolactinomas is challenging and requires a multidisciplinary approach. Clinical case: A 47-year-old woman was diagnosed with hyperprolactinemia after complaining of menstrual irregularities at 20 years old. No neoplastic lesion was identified in the suprasellar region, and 0.25 mg/week cabergoline was initiated. At 35 years’ old, an adenoma was suspected on the right side of the pituitary gland, though plasma prolactin values were sustained without any clinical symptoms. When the patient was 46 years old, her prolactin levels elevated to 202 ng/ml, and magnetic resonance imaging showed a tumor invaded bilateral cavernous sinuses. Because prolactin levels and tumor size continued to increase despite increasing the cabergoline dose to 1 mg/week, endoscopic transsphenoidal surgery was performed. The tumor nearly total removal, the postoperative prolactin levels decreased to 00, but started to increase again in a short period of time. Pathologic assessment revealed a high Ki-67 index (20%) and diffusely positive prolactin alongside negative expression of other anterior hormones. The tumor remained in the cavernous sinus and postoperative prolactin levels tended to increase over time. Cabergoline was restarted and increased to 7mg/week, although prolactin levels were not suppressed. Magnetic resonance imaging and computed tomography scanning showed no metastasis, and octreotide scintigraphy revealed no abnormal accumulation except for the tumor in the cavernous sinus. Radiation therapy was administered to the remaining tumor, and prolactin levels gradually decreased. Thereafter, hypercalcemia and high intact parathyroid hormone levels were found in the presence of left-inferior parathyroid enlargement, leading to a diagnosis of multiple endocrine neoplasia type 1 (MEN1). The patient had no family history of endocrine disease. MEN1 gene mutation was not detected by direct sequencing.

Discussion

Functional pituitary adenomas including prolactinomas and growth hormone-producing pituitary adenomas are usually benign with a Ki-67 index of approximately 1%, little mitosis, and slow progression 1) . However, pituitary adenomas in MEN1 patients have a higher rate of drug resistance and histological invasiveness than sporadic adenomas, which results in a higher postoperative recurrence rate and a lower normalization rate of approximately 40% 2) . For this case, close monitoring for tumor growth and metastasis was essential. References: 1) KontogeorgosG Endocrine 2005;27-352) Verges B, et al. J Clin Endocrinol Metab 2002; 87: 457-465.

Presentation: No date and time listed

Lymphocytic panhypophysitis and anti-rabphilin-3A antibody with pulmonary sarcoidosis

PURPOSE

To explore the clinical significance of anti-rabphillin-3A antibody for the differential diagnosis of lymphocytic panhypophysitis.

METHODS AND RESULTS

A 58-year-old Japanese man developed uveitis of unknown cause in 2017. In 2019, he became aware of polyuria. In August 2020, he noticed transient diplopia and was diagnosed with right abducens nerve palsy. At the same time, he complained of fatigue and loss of appetite. Head magnetic resonance imaging demonstrated enlargement of the pituitary stalk and pituitary gland, corresponding to hypophysitis. Hormone stimulation tests showed blunted responses with respect to all anterior pituitary hormones. Central diabetes insipidus was diagnosed on the basis of a hypertonic saline loading test. Taking these findings together, a diagnosis of panhypopituitarism was made. Computed tomography showed enlargement of hilar lymph nodes. Biopsies of the hilar lymph nodes revealed non-caseating epithelioid cell granulomas that were consistent with sarcoidosis. Biopsy of the anterior pituitary revealed mild lymphocyte infiltration in the absence of IgG4-positive cells, non-caseating granulomas, or neoplasia. Western blotting revealed the presence of anti-rabphilin-3A antibody, supporting a diagnosis of lymphocytic panhypophysitis. Because the patient had no visual impairment or severe uveitis, we continued physiological hormone replacement therapy and topical steroid therapy for the uveitis.

CONCLUSION

To the best of our knowledge, this is the first case of anti-rabphilin 3A antibody positive lymphocytic panhypophysitis comorbid with sarcoidosis, diagnosed by both pituitary and hilar lymph node biopsy. The utility of anti-rabphilin-3A antibody for the differential diagnosis of hypophysitis like this case should be clarified with further case studies.

Analysis of induced pluripotent stem cell clones derived from a patient with mosaic neurofibromatosis type 2

The diagnosis of mosaicism is challenging in patients with neurofibromatosis type 2 (NF2) subset due to low variant allele frequency. In this study, we generated induced pluripotent stem cells (iPSCs) were generated from a patient clinically diagnosed with NF2 based on multiple schwannomas, including bilateral vestibular schwannomas and meningiomas. Genetic analysis of the patient's mononuclear cells (MNCs) from peripheral blood failed to detect NF2 alteration but successfully found p.Q65X (c.193C>T) mutation in all separate tumors with three intracranial meningiomas and one intraorbital schwannoma, and confirming mosaicism diagnosis in NF2 alteration using deep sequencing. Five different clones with patient-derived iPSCs were established from MNCs in peripheral blood, which showed sufficient expression of pluripotent markers. Genetic analysis showed that one of five generated iPSC lines from MNCs had the same p.Q65X mutation as that found in NF2. There was no significant difference in the expression of genes related to NF2 between iPSC clones with the wild-type and mutant NF2. In this case, clonal expansion of mononuclear bone marrow-derived stem cells recapitulated mosaicism's genetic alteration in NF2. Patient-derived iPSCs from mosaic NF2 would contribute to further functional research of NF2 alteration.

Cystic Intracranial Recurrence of Olfactory Neuroblastoma without Accumulation on Fluorine-18-fluorodeoxyglucose Positron Emission Tomography

A 66-year-old man underwent multimodal treatment for olfactory neuroblastoma (ONB). When he was 72 years old, a cystic intracranial lesion without accumulation on fluorine-18-fluorodeoxyglucose positron emission tomography was detected. Surgical resection was performed when the patient was 73 years old. The pathological examination revealed recurrence of ONB, and the patient underwent focal irradiation. At age 81, he presented with a second recurrence in the right occipital lobe with radiological and pathological findings similar to the prior recurrence. This case suggests that pathological confirmation should be considered in cases with atypical radiological findings following the treatment of ONB.

ACT-5 Prognosis of IDH-mut lower-grade gliomas in Hokkaido University Hospital

Background: WHO grade 2 and 3 adult gliomas are nowadays getting together as lower-grade gliomas (LrGGs), but we had been recognized grade 3 (G3) tumors as high-grade and grade 2 (G2) tumors as low-grade. In this report, we investigate the treatment and prognosis of the patients with LrGG harboring IDH mutations in our institutions. Methods:We retrospectively review primary treatments and their prognosis for LrGG patients with IDH mutation since 2003. They categorized as astrocytomas and oligodendrogliomas according to 1p/19q loss-of-heterozygosity status. Prognosis were evaluated by overall survival. Postoperative primary treatments applied chemo-radiotherapy (CRT), radiotherapy only (RT), chemotherapy only (CT), and observation (Ob). Results: 36 astrocytomas and 60 oligodendrogliomas were identified. In astrocytomas, the patients with G3 (N=16) were treated by CRT (N=14) or CT (N=2), and the patients with G2 (N=20) were treated by CRT (N=2), RT (N=3), CT (N=3), or Ob (N=12). In oligodendrogliomas, the patients with G3 (N=34) were treated by CRT (N=32) or CT (N=2), and the patients with G2 (N=26) were treated by CRT (N=3), RT (N=1), CT (N=5), or Ob (N=17). 10-year survival rate (10yOS) of astrocytomas and oligodendrogliomas are 54% and 90%, respectively (p=0.002). According to histological malignancy, 10yOS of G3 and G2 astrocytomas were 54% and 54%, respectively (p=0.97) and that of G3 and G2 oligodendrogliomas were 86% and 100%, respectively (p=0.64). In both group, there are no different of prognosis according to histological malignancy. Discussion: There was no prognostic different between G2 and G3 astrocytomas in our institution. Since the treatment intensity for G2 and G3 astrocytomas were clearly different, the primary treatment for G2 astrocytomas might be insufficient. On the other hand, there were no prognostic different between G2 and G3 oligodendrogliomas in our institution, as with recent reports, so the primary treatment intensity for oligodendrogliomas should be appropriate.

Variations and natural history of primary intraparenchymal lesions associated with neurofibromatosis type 2

The study aimed to investigate the clinical implications and natural history of primary intraparenchymal lesions in patients with neurofibromatosis type 2. Radiological findings of 15 neurofibromatosis type 2 cases were retrospectively collected. Twenty-seven primary intraparenchymal lesions were observed in 7 out of 15 patients (47%). Cortical/subcortical T2 hyperintense lesions and enlarged Virchow-Robin spaces were the most common findings in five and four patients, respectively. During the follow-up period (median 84 months), one new primary intraparenchymal lesion was identified and increased lesions were observed in two cases on contrast-enhanced MRI. Surgical resection was performed in one case pathologically diagnosed with atypical meningioma. Twenty-five other lesions without contrast enhancement presented no apparent growth during follow-up. Although most primary intraparenchymal lesions are benign, a subset of cases would present newly developed or increased lesions on contrast-enhanced MRI. Careful monitoring is necessary for such cases, and pathological confirmation should be considered.

Immersive 3-Dimensional Virtual Reality Modeling for Case-Specific Presurgical Discussions in Cerebrovascular Neurosurgery

BACKGROUND

Adequate surgical planning includes a precise understanding of patient-specific anatomy and is a necessity for neurosurgeons. Although the use of virtual reality (VR) technology is emerging in surgical planning and education, few studies have examined the effectiveness of immersive VR during surgical planning using a modern head-mounted display.

OBJECTIVE

To investigate if and how immersive VR aids presurgical discussions of cerebrovascular surgery.

METHODS

A multiuser immersive VR system, BananaVisionTM, was developed and used during presurgical discussions in a prospective patient cohort undergoing cerebrovascular surgery. A questionnaire/interview was administered to multiple surgeons after the surgeries to evaluate the effectiveness of the VR system compared to conventional imaging modalities. An objective assessment of the surgeon's knowledge of patient-specific anatomy was also conducted by rating surgeons' hand-drawn presurgical illustrations.

RESULTS

The VR session effectively enhanced surgeons' understanding of patient-specific anatomy in the majority of cases (83.3%). An objective assessment of surgeons' presurgical illustrations was consistent with this result. The VR session also effectively improved the decision-making process regarding minor surgical techniques in 61.1% of cases and even aided surgeons in making critical surgical decisions about cases involving complex and challenging anatomy. The utility of the VR system was rated significantly higher by trainees than by experts.

CONCLUSION

Although rated as more useful by trainees than by experts, immersive 3D VR modeling increased surgeons' understanding of patient-specific anatomy and improved surgical strategy in certain cases involving challenging anatomy.

Neuromedin B Receptor Antagonist Suppresses Pomc Expression in AtT-20 Cells and Human Corticotroph Adenoma Cells

Objective: We previously reported that Neuromedin B (NMB) is expressed in murine pituitary corticotrophs under adrenal insufficiency (1). Because NMB is also expressed in several cancer cells and stimulates ACTH secretion, we hypothesized that NMB is related to corticotroph adenoma cell proliferation and hormone secretion. To examine this hypothesis, we investigated the expression of NMB and its receptor NMBR in human corticotroph adenoma and the effects of a NMBR antagonist on AtT-20 cells, a mouse corticotroph adenoma cell line, and patient-derived corticotroph adenoma cells. Methods: 1. NMB and NMBR expression in human pituitary adenoma: We performed real-time qPCR and immunostaining on human pathological specimens of corticotrophs, somatotrophs, and non-functioning pituitary adenoma to investigate NMB and NMBR expression. 2. Experiments in AtT-20 cells: We extracted mRNAs and proteins from AtT-20 cells after incubation with 100nM NMBR antagonist PD168368, and performed real-time qPCR and western blotting analyses to investigate Pomc expression. 3. Experiments in patient-derived corticotroph adenoma cells: We isolated surgically resected human corticotroph adenoma cells from patients who underwent trans-sphenoidal surgery and investigated POMC mRNA expression by real-time qPCR after incubation with PD168368. Statistical analysis: One-way ANOVA was employed to compare values among multiple groups. If the ANOVA revealed significant differences, the Tukey-Kramer post-hoc test was employed to compare values between two specific groups. Dunnett’s post-hoc test was employed to compare values with the control group. Statistical significance was defined as p < 0.05. Results: 1. NMB and NMBR expression levels were significantly higher in human corticotroph adenoma (13 and 33 times higher than non-functioning adenoma, respectively) than in somatotroph adenoma (2 and 3 times higher than non-functioning adenoma, respectively) and non-functioning adenoma in the qPCR analyses. Immunostaining confirmed higher expression of NMB and NMBR in corticotroph adenoma than in somatotroph and non-functioning adenoma. 2. Treatment with 100 nM PD168368 significantly suppressed Pomc mRNA and protein expression in AtT-20 cells by 22%±3% and 25%±10%, respectively. 3. Treatment with 1 µM PD168368 significantly suppressed POMC mRNA expression in human corticotroph adenoma cells by 18%±1%. Conclusions: NMB and NMBR were both expressed in human corticotroph adenoma, suggesting that NMB may stimulate adenoma cell proliferation and hormone secretion in autocrine or paracrine manners. Because the NMBR antagonist suppressed Pomc expression in both AtT-20 cells and human corticotroph adenoma cells, it may represent a potential treatment for Cushing disease. Reference: (1) Kameda H et al., Endocrinology 2014;155(7):2492-9.

Distinct TERT promoter C228T and C250T mutations in a patient with an oligodendroglioma: A case report

The majority of oligodendroglial tumors harbor mutations in the telomerase reverse transcriptase (TERT) gene (TERT) promoter and the isocitrate dehydrogenase 1/2 (IDH1/2) gene (IDH1/2), as well as 1p/19q codeletion. Generally, TERT promoter mutations, C250T and C228T, are mutually exclusive. We present a case of oligodendroglioma harboring both C250T and C228T mutations in TERT promoter. A 38-year-old man presented with grand mal seizures and underwent a resection surgery for a left frontal lobe tumor. He was pathologically diagnosed as having oligodendroglioma and was carefully observed. At 48 years of age, he underwent another resection surgery due to tumor regrowth, with the pathological diagnosis of anaplastic oligodendroglioma. Genetic analysis of the initial tumor specimen revealed IDH1 R132H mutation and both C250T and C228T mutations in TERT promoter. Using mutation-specific primers, two mutations were considered to be distributed in different alleles. In the tumor specimen obtained during the second surgery, IDH1 R132H mutation was detected to be similar to that of the initial specimen; however, only C228T mutation was detected in TERT promoter. The 1p/19q codeletion was detected in both the initial and recurrent tumor specimens. According to the sequencing data from the two tumor specimens, although TERT promoter mutation has been considered to be an early genetic event in the tumorigenesis of oligodendroglial tumors, it is likely that the C250T and C228T mutations in TERT promoter are subclonally distributed in the same tumor specimen of the present case.

High-grade neuroepithelial tumor with BCL6 corepressor-alteration presenting pathological and radiological calcification: A case report

A 5-year-old girl presented with headache and vomiting. Head computed tomography and magnetic resonance imaging showed a right frontal lobe tumor with marked calcification. The patient underwent resection surgery with suspicion of anaplastic ependymoma, and the tumor was gross totally removed. Pathological examination revealed areas of dense tumor cells with a high nucleocytoplasmic ratio and myxoid areas consisting of tumor cells with a round-shaped nucleus and eosinophilic cytoplasm. Perivascular pseudorosette, necrosis, circumscribed growth, and microcalcification were also observed. Immunohistochemistry demonstrated negative staining for glial fibrillary protein and epithelial membrane antigen. Diagnosis of a high-grade neuroepithelial tumor (HGNET) with BCL6 corepressor (BCOR) alteration was made based on pathological findings and internal tandem duplication in the exon 15 of BCOR. Although calcification on radiological and pathological examination is not typical, it would be essential to recognize that calcification could appear in HGNET-BCOR.

Clinical Outcome of Cytoreductive Surgery Prior to Bevacizumab for Patients with Recurrent Glioblastoma: A Single-center Retrospective Analysis

Bevacizumab (BEV) is a key anti-angiogenic agent used in the treatment for recurrent glioblastoma multiforme (GBM). The aim of this study was to investigate whether cytoreductive surgery prior to treatment with BEV contributes to prolongation of survival for patients with recurrent GBM. We retrospectively analyzed the treatment outcomes of 124 patients with recurrent GBM who were initially treated with the Stupp protocol between 2006 and 2019. Given that BEV has only been available in Japan since 2013, we grouped the patients into two groups according to the time of first recurrence: the pre-BEV group (N = 51) included patients who had recurrence before BEV approval, and the BEV group (N = 73) included patients with recurrence after BEV approval. The overall survival after first recurrence (OS-R) was analyzed according to the treatment strategy. Among 124 patients, 27 patients (19.4%) received cytoreductive surgery. There were nine cases in the pre-BEV group and 18 cases in the BEV group. Although the mean extent of resection for both groups was almost equal, OS-R was significantly different. The median OS-R was 8.1 m in the pre-BEV group and 16.3 m in the BEV group (P = 0.007). Multivariate analysis revealed that the unavailability of BEV postoperatively (P = 0.03) and decreasing performance status by surgery (P = 0.01) were significant poor prognostic factors for survival after surgery. With the advent of BEV, cytoreductive surgery might provide superior survival benefit at the time of GBM recurrence, especially in cases where surgery can be performed without deteriorating the patient's condition.

Use of magnetic resonance venography for inferior petrosal sinus sampling

BACKGROUND

Inferior petrosal sinus (IPS) sampling (IPSS) is a transvenous interventional procedure performed to diagnose Cushing's disease. The reported IPSS failure rate is approximately 10% because IPS catheter delivery is conducted blindly and is challenging because of IPS anatomical variations. This study aimed to evaluate the usefulness of preprocedural magnetic resonance venography (MRV) for assessing IPS access routes before IPSS.

METHODS

Nineteen consecutive patients who underwent IPSS at a single university hospital in Japan were retrospectively studied. A preprocedural MRV protocol optimized to visualize the IPS before IPSS was established and utilized in the eight most recent cases. An IPSS procedure was considered successful when bilateral IPS catheterization was accomplished. Patient demographics, IPSS success rate, and radiation dose required during IPSS were compared between two groups: MRV group (N = 8) and no-MRV group (N = 11) before IPSS.

RESULTS

There were no significant differences in age, sex, and IPSS success rates between the groups. The average radiation dose was 663.6 ± 246.8 (SD) mGy and 981.7 ± 389.5 (SD) mGy in the MRV group and no-MRV group, respectively. Thus, there was a significant reduction in radiation exposure in the MRV group (p = 0.044). Catheterization of the left IPS was unsuccessful in only one patient in the MRV group owing to IPS hypoplasty, as found on the MRV.

CONCLUSIONS

Hypoplastic IPSs occur in patients and can complicate IPSS. Preprocedural MRV assessment is useful for understanding venous anatomy and preventing unnecessary intravenous catheter manipulation during IPSS, which involves blind manipulation around the IPS.

GCT-08. PROTON BEAM RADIOTHERAPY FOR PEDIATRIC AND YOUNG-ADULT PATIENTS WITH INTRACRANIAL GERM CELL TUMOR

BACKGROUND

To reduce treatment-related adverse events in pediatric and young-adult patients with brain tumors, proton beam radiotherapy (PBT) has recently been performed instead of conventional X-ray radiotherapy. However, whether PBT is as effective as X-ray radiotherapy has not been sufficiently investigated, especially in patients receiving whole-ventricular irradiation.

METHODS

We report a retrospective observation of 15 patients with intracranial germ cell tumors (GCT), who received PBT at our institution from April 2014 to September 2019. We evaluated their clinical course, short-term adverse events, and prognosis. RESULTS/

CONCLUSION

Fifteen patients (9 males and 6 females; median age 13 years) who received PBT following induction chemotherapy were analyzed. Nine patients received 23.4–27.0 GyE of whole-ventricular irradiation due to GCT in the pituitary gland, pineal body, or hypothalamic area. Three patients received 23.4 GyE of whole-brain irradiation: one of them had boost irradiation for basal ganglia. Three patients received 30.6 GyE of craniospinal irradiation (CSI). Six of the 15 patients experienced nausea (grade 2, according to the CTCAE version 4.0). Four patients, including two who received CSI, showed myelosuppression: decrease in white blood cell count, lymphocyte cell count, and neutrophil count (grade 3). No other severe short-term adverse events of >grade 2 was observed in any of the patients. At a median follow-up of 21 months (2‐62 months) after irradiation. all patients are alive without recurrence. Our results may be encouraging and further investigations with a larger scale is warranted.

GCT-10. CAN HIGH LEVEL SERUM hCG-β BE CONSIDERED EQUIVALENT TO A DIAGNOSIS OF CHORIOCARCINOMA IN PRIMARY CENTRAL NERVOUS SYSTEM GERM-CELL TUMOR?

BACKGROUND

Primary central nervous system(CNS) choriocarcinoma(CC) is very rare and has the poorest prognosis among germ cell tumor (GCT). CC usually has extremely high level (HL) of serum beta-human chorionic gonadotropin (bhCG) over than 1,000 mIU/ml. Some studies assign HL bhCG cases to poor prognosis group even without biopsy. The purpose of this study was to find out if there was a good prognosis subset in the HL bh group.

MATERIALS AND METHODS

We analyzed 103 cases diagnosed with GCT from 1998 to 2019 in Hokkaido University Hospital and reviewed the literature of CNS CC and bhCG. Survival was assessed using Kaplan-Meier method and log-rank statistics between the group with CC component and that with no CC component but HL bhCG.

RESULTS

One out of 103 our cases was diagnosed as a mixed GCT with CC component and did not respond to treatment and died 9 months later. Two cases were treated as CC because of HL bhCG (1,226 and 2,739 mIU/ml) despite that the biopsy showed only germinomas and survived(105 and 37 months), that is, no CC component. Combining our cases with 69 cases in the literature, all 7 cases with no CC component but HL bhCG survived but the median survival of the other 65 cases with CC component was 38.2 months (P=0.02).

CONCLUSION

This study has a limitation of selection bias, however, it suggests that patients with no CC component but HL bhCG may have a better prognosis.

GCT-31. DIAGNOSTIC CAPABILITY OF CSF-PLAP ON INTRACRANIAL GERM CELL TUMOR

BACKGROUND

Since the majority of intracranial germ cell tumor(GCT) is sensitive for chemoradiation, biopsy specimens are usually tiny and not enough for accurate pathological diagnosis. To supply complementary diagnostic information, a-fetoprotein or human chorionic gonadotropin-b are important biomarkers. Recently CSF-placental alkaline-phosphatase(PLAP) is also reported as an additional biomarker in intracranial GCT. This study’s purpose is to evaluate the significance of CSF-PLAP.

METHODS

CSF-PLAP was obtained from the patients with the intraventricular and periventricular tumor before any adjuvant therapy. Definitive diagnoses were made by histopathological information and/or their clinical courses; GCT(germinoma or non-germinomatous GCT(NGGCT)) or other tumors. In GCT, the relationship between CSF-PLAP and tumor reduction volume was evaluated. Tumor volumes were calculated on gadolinium-enhanced T1-weighted magnetic resonance imaging before and after initial chemoradiotherapy.

RESULTS

Between 2005 and 2019, 42 patients were studied: 24 with GCT and 18 with others. CSF-PLAP value in patients with GCT was significantly higher than those with others: the Specificity was 88% and the sensitivity was 95% at the cutoff value of 8.0 pg/ml. For GCT patients, CSF-PLAP value tended to be higher in germinoma(n=12, mean 4756 pg/ml), compared to the value in NGGCT(n=7, mean 332 pg/ml), although there was no statistical difference. There was a significant positive correlation between initial CSF-PLAP value and tumor reduction volume.

CONCLUSION

CSF-PLAP is a useful tumor marker for GCT differentiating from the other tumors located in intraventricular and periventricular region and CSF-PLAP value might correlate with the volume of germinomatous component of the tumor.

SURG-02. INITIAL MANAGEMENT OF HYDROCEPHALUS IN THE PEDIATRIC AND YOUNG-ADULT PATIENTS WITH BRAIN TUMORS; THE EFFICACY OF LONG-TERM INDWELLING EXTERNAL VENTRICULAR DRAINAGE

BACKGROUND

Pediatric and Young-Adult (AYA) brain tumors often present with hydrocephalus. As temporary cerebrospinal fluid (CSF) diversion procedure, we perform long-term indwelling external ventricular drainage (EVD) in the case of the management of CSF diversion more than two weeks presumably. The aim of this study is to investigate the initial management for hydrocephalus in pediatric /AYA patients with brain tumor, especially about long-term EVD.

MATERIALS AND METHODS

The patients less than 30 years of age diagnosed with brain tumor between 2005 and 2019 were retrospectively analyzed. Procedures of long-term EVD were similar to that of ventriculoperitoneal shunt (VPS) operation. Using flow-control VPS system, peritoneal catheter passed out of the body at the anterior chest, and distal end of the catheter was connected to standard EVD system.

RESULTS

In total of 345 patients with brain tumor, 109 had hydrocephalus at presentation. Among them, 25 patients (23%) underwent long-term EVD. The main reasons for selecting long-term EVD were to avoid intraperitoneal dissemination (n=13), and to maintain longer period of CSF diversion for the treatment of tumor (n=12). The median of long-term EVD was 38 days (range: 12 – 222 days). Although one case suffered from drainage tube occlusion at 59 days, there were no other complications such as infection or accidental evulsion. Eventually, 3 cases required permanent VPS for persistent hydrocephalus.

CONCLUSION

Long-term EVD is safe and effective option for CSF diversion. This procedure should be taken into consideration if patients have a risk of dissemination and may elude permanent VPS.

RONC-16. PROTON BEAM THERAPY FOR PATIENTS WITH INTRACRANIAL EPENDYMOMA UNDER 3 YEARS OLD: INITIAL CLINICAL OUTCOMES

BACKGROUND

Proton beam therapy (PBT) provides dosimetric benefits in sparing normal tissue when treating pediatric patients with brain tumors. We report the preliminary clinical outcomes of surgery and adjuvant PBT for patients under 3 years old diagnosed as intracranial ependymoma at our institute.

METHODS

This is a retrospective review of the medical records for 3 children with ependymoma in the fourth ventricle, diagnosed between March 2013 and September 2019. PBT was performed after tumor resection in all the patients.

RESULTS

Gross total resection was achieved in 2 males and 1 female patients with fourth ventricle WHO grade II to III ependymoma at 15, 18, and 37 months old. All the patients received adjuvant PBT (54.0 GyE/30 fractions) to the postoperative tumor bed under general anesthesia or sedation. PBT was acutely well tolerated, with mostly mild alopecia and skin reactions at the irradiated sites. At a median follow-up of 54 months (4–59 months) after irradiation, all the patients are alive without recurrence. No serious late adverse events were observed in any of the patients.

CONCLUSION

The number of patients in this study remains small for drawing any definite conclusion, however our preliminary results are still encouraging. Further studies of a large number of pediatric patients with long term follow-up are needed to more fully assess tumor control and late adverse events.

ML-04 The influence of surgical intervention for high-dose Methotrexate chemotherapy in the patients with primary central nervous system lymphoma

Object: Surgical resection is not the standard of treatment for primary central nervous system lymphoma (PCNSL). Some recent studies suggest that resection might be beneficial. The aim of this study was to examine the effect of surgical treatment in terms of the time from surgery to chemotherapy.

Methods: We retrospectively analyzed all patients with PCNSL treated at Hokkaido University Hospital between 2001 and 2018 to assess the effect of selection for resection on the response of Methotrexate chemotherapy. We identified the days from surgery to chemotherapy, complications, the response of Methotrexate (CR/CRu rate) and prognostic factors including progression free survival (PFS) and overall survival (OS).

Results: A total 105 patients were identified. 84 patients underwent biopsy and 21 patients underwent surgical resection. Their median age were 63 [31–78] and 68 [44–77], respectively. Their Karnofsky Performance Status (KPS) were 70 [30–100] and 70 [40–100]. There were any significant difference. Patients undergoing biopsy and those undergoing resection had comparable rates of complications for all complication type. Overall, 4 biopsy patients and 5 resection patients experienced at least one complication. They were composed of 2 asymptomatic bleeding, 1 wound abscess, 1 hydrocephalus in biopsy patients, 1 epidural abscess, 1 epilepsy, 1 chronic subdural hematoma, 2 temporary hemiparesis. Although the days from surgery to chemotherapy were significantly shorter in patients underwent biopsy than in those underwent resection (P=0.0015), PFS was significantly longer in patients underwent resection than in those underwent biopsy (P=0.0403), whereas there was no difference in OS.

Discussion: Resection could delay the postoperative treatment. In this study, there was a significant delay of postoperative treatment in resection patients, however, CR/CRu rate after MTX was significantly better in those underwent resection than biopsy. We can see that resection for PCNSL might not necessarily worsen the prognosis.

Diagnostic Capability of Cerebrospinal Fluid-Placental Alkaline Phosphatase Value in Intracranial Germ Cell Tumor

OBJECTIVE

Most types of intracranial germ cell tumors (IGCTs) are sensitive to chemoradiation. However, biopsy specimens are usually small and thus cannot be used for obtaining an accurate pathological diagnosis. Recently, the cerebrospinal fluid (CSF) placental alkaline phosphatase (PLAP) value has been considered a new biomarker of IGCTs. The present study aimed to evaluate the discriminatory characteristics of the CSF-PLAP value upon diagnosis and at the time of recurrence in patients with IGCTs.

METHODS

Between 2015 and 2019, this study included 37 patients with tumors located in the intraventricular and/or periventricular region. The CSF-PLAP level was assessed before the patients received any treatment. The PLAP level was evaluated during and after first-line chemoradiotherapy in 7 patients with IGCTs. The CSF-PLAP values were compared according to histological diagnosis, and the correlation between these values and radiographical features was assessed. The CSF-PLAP values of 6 patients with IGCTs with suspected recurrence were evaluated based on neuroimaging findings.

RESULTS

The CSF-PLAP values were significantly higher in patients with IGCTs than in those with other types of brain tumor (n = 19 vs. 18; median: 359.0 vs. <8.0 pg/mL). The specificity and sensitivity were 88 and 95%, respectively, with a cutoff value of 8.0 pg/mL. In patients with IGCT, the CSF-PLAP value was higher in patients with germinoma than in those with nongerminomatous germ cell tumors (n = 12 vs. 7; median: 415.0 vs. 359.0 pg/mL). Regarding the time course, the CSF-PLAP value decreased to below the detection limit after the reception of first-line chemoradiotherapy in all 7 patients. A significant correlation was observed between the initial CSF-PLAP value and the tumor reduction volume after receiving first-line chemoradiotherapy (p < 0.0003, R2 = 0.6165, logY = 1.202logX - 1.727). Among the patients with suspected IGCT recurrence (n = 6), the CSF-PLAP value was high in patients with recurrence (n = 3; median: 259.0 pg/mL), and that in patients (n = 3) without recurrence was below the lower detection limit.

CONCLUSIONS

The CSF-PLAP level is a useful biomarker during the initial diagnosis of IGCTs and at the time of recurrence. It may be associated with the volume of germinomatous components of tumors.

Association of the FGFR1 mutation with spontaneous hemorrhage in low-grade gliomas in pediatric and young adult patients

OBJECTIVE

The authors aimed to investigate genetic alterations in low-grade gliomas (LGGs) in pediatric and young adult patients presenting with spontaneous hemorrhage.

METHODS

Patients younger than 30 years of age with a pathological diagnosis of World Health Organization (WHO) grade I or II glioma and who had undergone treatment at the authors' institution were retrospectively examined. BRAF V600E, FGFR1 N546/K656, IDH1 R132, IDH2 R172, and KIAA1549-BRAF (K-B) fusion genetic alterations were identified, and the presence of spontaneous tumoral hemorrhage was recorded.

RESULTS

Among 66 patients (39 with WHO grade I and 27 with grade II tumors), genetic analysis revealed K-B fusion in 18 (27.3%), BRAF V600E mutation in 14 (21.2%), IDH1/2 mutation in 8 (12.1%), and FGFR1 mutation in 4 (6.1%). Spontaneous hemorrhage was observed in 5 patients (7.6%); 4 of them had an FGFR1 mutation and 1 had K-B fusion. Univariate analysis revealed a statistically significant association of an FGFR1 mutation and a diencephalic location with spontaneous hemorrhage. Among 19 diencephalic cases including the optic pathway, hypothalamus, and thalamus, an FGFR1 mutation was significantly associated with spontaneous hemorrhage (p < 0.001). Four FGFR1 mutation cases illustrated the following results: 1) a 2-year-old female with pilomyxoid astrocytoma (PMA) harboring the FGFR1 K656E mutation presented with intraventricular hemorrhage (IVH); 2) a 6-year-old male with PMA harboring FGFR1 K656E and D652G mutations presented with intratumoral hemorrhage (ITH); 3) a 4-year-old female with diffuse astrocytoma harboring FGFR1 K656M and D652G mutations presented with IVH; and 4) a young adult patient with pilocytic astrocytoma with the FGFR1 N546K mutation presented with delayed ITH and IVH after 7 years of observation.

CONCLUSIONS

Although the mechanism remains unclear, the FGFR1 mutation is associated with spontaneous hemorrhage in pediatric and young adult LGG.

ACT-21 PRIMARY EXPERIENCE OF NOVOTTF THERAPY FOR THE PATIENTS WITH GBM IN OUR INSTITUTION

BACKGROUND

Based on EF-14 clinical trial, NovoTTF therapy prolong overall survival in the patients with GBM. However, NovoTTF treatment does not become standard therapy because treatment procedures are cumbersome and potentially impose psychological burden on patients who suffer from dismal disease. In our institution, we can choose NovoTTF therapy as one of the treatment options for GBM patients since June 2018. In this report, we summarized primary experience of this novel treatment.

MATERIALS AND METHODS

Adult patients with primary GBM diagnosed after June 2018 were retrospectively reviewed. We investigated the suggestion of NovoTTF, patients’ acceptance, the reason of rejection of NovoTTF, and the condition of NovoTTF treatment.

RESULTS

Among 22 GBM patients, 12 cases were proposed NovoTTF treatment in actual. In 10 cases who were not proposed NovoTTF, the reasons were 1) poor performance status (KPS 50% or less); 7 cases, oldest-old; 1 case, unavailable care person; 2 cases. In 12 cases who were proposed NovoTTF, 5 cases (42%) accepted and performed this therapy. Remaining 7 cases did not accept NovoTTF because rejection of shaving hair; 1 case, troublesome for daily work; 2 cases, refusal due to cumbersome procedure; 2 cases, unavailable cooperation with care person(s); 2 cases. 5 cases treated NovoTTF were 3 males and 2 females, and the median age was 67yo (range 25yo-69yo). All patients were continued NovoTTF for 1–7 months without major complication. In two cases, minor skin trouble was observed, but easy to handle by putting ointment.

CS-09 PROPOSAL OF A NEW CLASSIFICATION FOR DETERMINING THERAPEUTIC STRATEGY ACCORDING TO THE PROGRESSION OF OLFACTORY NEUROBLASTOMA

INTRODUCTION

Olfactory neuroblastoma (ONB) is a rare type of malignancy that infiltrates and propagates from the nasal cavity to the anterior skull base and into the cranium. Various treatment strategies have been used at different institutions and time of treatment. Although the staging system proposed by Kadish is commonly adopted has not proven useful for predicting prognosis or choosing among treatment strategies. Factors to be considered have increased accordingly, for example, whether to perform ESS alone or in combination with craniotomy, whether to try preserving the olfactory sense and whether to use neoadjuvant chemotherapy. In this study, we reviewed ONB cases treated at our institution to propose a new classification system to help determine treatment strategies.

METHODS

Thirty-four patients treated at Hokkaido University were included. Stages of craniocaudal progression were defined as Nasally/Paranasally localized (NP), Frontal Base progression (FB), and Brain invasion (BI). Stages of lateral progression were defined as Midline (M) or Lateral extension (L), and Unilateral (U) or Bilateral (B).

RESULTS

Between 2008 and 2016, patients at the BI stage were proactively treated with neoadjuvant chemotherapy and achieved long-term survival (mean overall survival, 64.2 months). However, no standard way of choosing among treatment options was established. M-stage patients underwent concurrent craniotomy. From 2017 onwards, 5 patients were treated according to the new classification system. All were FB-M cases, including 4 cases of B disease, in which ESS alone followed by radiotherapy was used. One patient in the FB-M-U category underwent unilateral resection and the olfactory sense was preserved. In general, the treatment with ESS alone appeared to be preferred for M disease, and surgery after neoadjuvant chemotherapy was advisable for BI cases.

CONCLUSION

The result suggests that the new classification system is helpful to decide the treatment strategy according to the progression of ONB.

Overexpression of CD44 is associated with a poor prognosis in grade II/III gliomas

PURPOSE

Overexpression of CD44 has been detected in many types of tumor tissues. Moreover, CD44 is recognized as a cancer stem cell marker for many cancers. However, the prognostic value of CD44 for glioma patients has not yet been clarified. The authors tried to explore the impact of CD44 expression on grade II/III glioma patients.

METHODS

To assess the RNA expression levels of CD44 in glioma tissues and normal brain tissues, meta-analyses were conducted in the online Oncomine database. The mRNA expression levels of CD44, CD44s, and CD44v2-v10 in 112 grade II/III glioma patients in Hokkaido University Hospital (HUH) were detected by qPCR. The RNA-seq data and clinical data of grade II/III glioma patients were obtained from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases.

RESULTS

Based on the Oncomine database, CD44 has significantly high expression in glioma tissues as compared with normal tissues. We explored the clinical relevance of CD44 mRNA expression based on the HUH cohorts, the TCGA cohorts, and the CGGA cohorts. In survival analysis, high mRNA expression of CD44 was correlated with poor overall survival and poor progression-free survival in grade II/III glioma patients. Multivariate Cox regression analyses confirmed CD44 as an independent prognostic factor for grade II/III glioma patients.

CONCLUSIONS

The present study suggests that overexpression of CD44 is associated with a poor prognosis for grade II/III glioma patients. Moreover, our findings suggest that CD44 could serve as a prognostic biomarker in grade II/III glioma patients.

A Rare Case of Idiopathic Temporal Muscle Abscess in a Nine-month-old Infant

Temporal muscle abscess in children usually occurs from acute otitis media, and rapid progression and concomitant infectious disease often make it easy to diagnose. We report a rare case of a nine-month-old infant who showed right temporal mass with no evidence of infection. Computed tomography showed an osteolytic round mass, and magnetic resonance imaging revealed heterogenous enhancement with a high apparent diffusion coefficient. Malignant tumor was first suspected, but an open biopsy revealed the swelling to be temporal muscle abscess. It should be noted that temporal abscess may mimic the features of a malignant tumor, and multiple examinations should be performed for an accurate diagnosis.

Sonodynamic Therapy for Malignant Glioma Using 220-kHz Transcranial Magnetic Resonance Imaging-Guided Focused Ultrasound and 5-Aminolevulinic acid

Sonodynamic therapy (SDT) is used to treat various malignancies and can be applied to brain tumors using a transcranial magnetic resonance imaging-guided focused ultrasound (TcMRgFUS) device. This study investigated the efficacy of 220-kHz TcMRgFUS combined with 5-aminolevulinic acid (5-ALA) on malignant glioma in vitro and in vivo. F98 cells were irradiated with focused ultrasound (FUS) (4000 J, 20 W, 240 s, 100% duty cycle, target medium temperature <40°C) after treatment with 200 µg/mL 5-ALA, and cell viability and apoptosis were evaluated with the water-soluble tetrazolium-1 assay, triple fluorescent staining and Western blot analysis 20 h later. The anti-tumor effects of 5-ALA combined with FUS (500 J, 18 W, 30 s, 100% duty cycle, 10 repeats, target tissue temperature ≤42°C) were assessed on the basis of changes in tumor volume determined by MRI and histopathological analysis before and after treatment. The FUS/5-ALA combination reduced cell viability by inducing apoptosis and suppressed tumor proliferation and invasion as well as angiogenesis in vivo, while causing minimal damage to normal brain tissue. SDT with 220-kHz TcMRgFUS and 5-ALA can be safely used for the treatment of malignant glioma.

Retrosigmoid Intradural Suprameatal Approach for Petroclival Meningioma

Background  Anterior transpetrosal approach and the combined transpetrosal approach are the major surgical approaches for petroclival meningiomas. However, anterior petrosectomy is not preferable in cases with postoperative venous drainage disorder of the sylvian vein due to anatomical variations. Here we present a case of the successful removal of petroclival meningioma by the retrosigmoid intradural suprameatal approach (RISA).

Case Presentation  The patient was a 59-year-old woman with incidentally detected right petroclival meningioma. Although she had no neurological deficit, the tumor manifested with gradual growth on annual magnetic resonance imaging (MRI) during an 8-year follow-up. Three-dimensional computed tomography venography (3D–CTV) revealed sphenobasal type of the sylvian vein throughout the lateral side of the foramen ovale. Because the suprameatal tubercle was an obstacle to observe the Meckel's cave, RISA was selected for complete tumor excision. RISA could provide an excellent operative field around the Meckel's cave to confirm the remnant tumor. Postoperative MRI showed no evidence of the tumor, and the patient was discharged without any neurological deficit.

Conclusion  RISA can provide a favorable operative field for petroclival meningioma, particularly for cases with high risk of postoperative complications related to the sylvian vein.

The link to the video can be found at: https://youtu.be/cfci_zk0StU .

The prognostic improvement of add-on bevacizumab for progressive disease during concomitant temozolomide and radiation therapy in patients with glioblastoma and anaplastic astrocytoma

BACKGROUND

Although newly diagnosed high-grade glioma patients in Japan can receive bevacizumab (BEV) as first-line chemotherapy, randomized clinical trials have not shown a survival benefit for BEV for these patients. In this study, we investigated whether selective add-on BEV for patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA) improves prognosis, in cases where tumors were continuously growing during radiotherapy concomitant with temozolomide (TMZ).

METHODS

We conducted a retrospective survey of the overall survival (OS) of patients with GBM/AAs who were treated in our institution between 2006 and 2016. Patients whose tumors were continuously growing regardless of radiotherapy were categorized as the "progressive" group; remaining patients were categorized as the "non-progressive" group. Since 2013, patients in the "progressive" group received add-on BEV therapy with the Stupp regimen during or just after radiotherapy.

RESULTS

Of 151 GBM/AA patients, 34 (22.5%) were categorized in the "progressive" group. Median OSs of the "progressive" and "non-progressive" groups were 13.2 months and 25.3 months, respectively (P<0.001). Twelve patients in the "progressive" group received add-on BEV therapy, and their median OS was 20.2 months; whereas for the remaining 22 patients in the "progressive" group who were treated before the BEV era, their median OS was 10.5 months. In the "progressive" group, add-on BEV significantly extended OS (P=0.018) and was the lone clinical factor of better prognosis.

CONCLUSIONS

We found that, for patients with GBM/AAs whose tumors were continuously growing during radiotherapy, add-on BEV treatment resulted in survival benefits.

Application of endoscopic ultrasonography to intraventricular lesions

BACKGROUND

Anatomical landmarks such as choroid plexus and foramen of Monro are very important to undergo intraventricular surgery safely and effectually. These landmarks would be unclear in cases with a huge cyst or repeat surgery. We report the usability and precautions to apply a bronchoscope with an ultrasonic convex probe to intraventricular surgery.

METHODS

Two patients diagnosed with obstructive hydrocephalus, one with a large cyst and the other with recurrent craniopharyngioma in the third ventricle, were applied to the EBUS system.

RESULTS

In both patients, the EBUS system was applied safely, and lesions beyond the wall of ventricles or the cyst were visible. Color Doppler ultrasonography detected choroid plexus and internal cerebral veins. Furthermore, we performed real-time ultrasound-guided cyst puncture safely on the case with a large cyst. The most important precaution is that the curved portion of the EBUS system is too long to be bent within cerebral ventricles.

CONCLUSIONS

The new EBUS system with an ultrasonic convex probe is a novel and effectual device to perform intraventricular surgery.

[Risk Factors for Adverse Events after Implantation of BCNU Wafers in High-grade Gliomas]

BACKGROUND

In Japan, patients with malignant glioma have been treated with BCNU wafers (Gliadel®) since January 2013. Several adverse events(AEs)associated with implantation of BCNU wafers, including cerebral edema or cyst formation, are recognized. Here, we report a retrospective review of the experience with implantation of BCNU wafers in our institutions and our findings regarding the risk factors for the AEs.

METHODS

We reviewed the records of patients with malignant glioma who were implanted with BCNU wafers between April 2013 and September 2014. Their AEs were examined clinically and radiologically and evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) grading. For investigating the association between risk factors and incidence of AEs, histological diagnosis, extent of resection, and period of BCNU wafers implantation surgery were selected as possible risk factors.

RESULTS

Twenty-one patients were included in this investigation. There were no associations among incidence of AEs and histological diagnosis or extent of tumor resection. However, regarding the period of BCNU wafers implantation, additional resection for newly diagnosed tumors and resection for recurrent tumors tended to increase the rate and severity of AEs, especially cerebral edema, compared to primary resection.

CONCLUSION

In cases of BCNU wafers implantation, the incidence and degree of AEs might increase if additional resection for newly diagnosed tumors or resection for recurrent tumors is performed. Our investigation revealed that AEs associated with implantation of BCNU wafers tend to occur in the repeated glioma surgery.

Idiopathic fourth ventricle outlet obstruction successfully treated by endoscopic third ventriculostomy: a case report

Introduction

Fourth ventricle outlet obstruction (FVOO) is a rare cause of obstructive hydrocephalus. We describe a case of idiopathic FVOO that was successfully treated with endoscopic third ventriculostomy (ETV).

Case report

A 3-year old boy without any remarkable medical history presented with a headache and vomiting. Computed tomography (CT) images, which had incidentally been taken 2 years previously due to a minor head injury, showed no abnormality. Magnetic resonance imaging on admission showed tetra-ventricular hydrocephalus associated with the dilatation of the fourth ventricle outlets, without any obstructive lesions. However, CT ventriculography, involving contrast medium injection through a ventricular catheter, suggested mechanical obstruction of the cerebrospinal fluid (CSF) at the fourth ventricle outlets. Thus, the patient was diagnosed with FVOO and ETV was performed; the hydrocephalus was subsequently resolved. Although hydrocephalus recurred 1 year postoperatively, re-ETV for the highly stenosed fenestration successfully resolved this condition.

Conclusions

ETV should be considered for FVOO treatment, particularly in idiopathic cases without CSF malabsorption.

Postoperative Acute Submandibular Sialadenitis after Neurosurgery: Two Case Reports and a Review of the Literature

This article details two case reports and reviews the extant literature concerning acute postoperative submandibular sialadenitis occurring in the side contralateral to the operated site after neurosurgery. Although its precise pathogenesis remains to be elucidated, it is likely related to intraoperative compression of the submandibular gland and surrounding tissues, caused by head positioning and the endotracheal tube. Submandibular swelling rapidly deteriorates after surgery, and emergent airway protection is required in most cases in order to avoid fatal airway obstruction. To avoid serious sequelae, we should be aware of acute submandibular sialadenitis that occurs contralateral to the surgical side, which, although rare, is more probable after posterior fossa surgery. When it occurs, early airway protection is crucial, and the following conservative treatment could provide a good prognosis.

Porphyrin derivatives-mediated sonodynamic therapy for malignant gliomas in vitro

Because it is highly infiltrative, malignant glioma is a cancer with a poor prognosis despite multidisciplinary treatment strategies, such as aggressive surgery and chemoradiotherapy, necessitating new therapeutic approaches to control migration of tumor cells. In our study, we investigated the efficacy of sonodynamic therapy of glioma cells in vitro using porphyrin derivatives, including 5-aminolevulinic acid, protoporphyrin IX and talaporfin sodium, as sonosensitizers. These substances have been known to accumulate in glioma cells and are expected to have cytotoxic effects on sonication. Our study found that the cytotoxicity of sonication of glioma cells is enhanced by each sonosensitizer and that the efficacy of sonodynamic therapy may depend on the degree of intracellular accumulation of sonosensitizer. Also, the study suggests that induction of apoptosis is a major mechanism underlying cell death. Though further investigations are necessary, our preliminary result indicates a potential for sonodynamic therapy with sonosensitizers in glioma treatment.

Regression of dural arteriovenous fistulae after venous flow reconstructive surgery in a case with hemangiopericytoma at the confluence of sinuses

Background

The mechanism by which acquired dural arteriovenous fistula (dAVF) develops is still unclear. Few cases have been reported with both dAVF and intracranial tumors, and in these few cases the authors have proposed that induced venous hypertension may lead to the pathogenesis of dAVF. We experienced a case of intrasinusoidal hemangiopericytoma (HPC) with dAVF development. In addition to its rare pathology and tumor location, this case showed regression of dAVF immediately after tumor removal.

Case Report

The patient was a 23-year-old man who developed progressively worse headaches and papilledema. The HPC was located entirely inside the confluence of the sinuses (CoS) and resulted in venous sinus occlusion. Cerebral angiography demonstrated a dAVF located in the straight sinus, upstream of the occluded CoS, which was fed by the dural branch of the posterior cerebral artery. After the endovascular embolization of the tumor feeders, subsequent surgery included venous reconstruction in addition to tumor excision. Although the dAVF was not treated with an endovascular procedure or surgery, postoperative angiography revealed complete disappearance of the dAVF.

Conclusion

We conclude that venous reconstructive surgery greatly contributed to the immediate regression of the dAVF. When planning the treatment strategy for such cases, it should be remembered that acquired dAVF may regress due to the normalization of venous hypertension.

Thalamic arteriovenous malformation fed by the artery of Percheron originating from the contralateral posterior cerebral artery in a child

PURPOSE

Artery of Percheron (AOP) is a rare variant of thalamoperforating artery with a single common trunk feeding both thalami and with or without contribution to the rostral midbrain. We report the first case of thalamic arteriovenous malformation (AVM) fed by AOP with hemorrhagic onset.

METHODS

A 12-month-old girl suddenly weakened and developed coma. Left thalamic hemorrhage was detected with the third and both lateral ventricles' hematoma. Thalamic AVM was discovered to be fed by an AOP originating from the contralateral posterior cerebral artery.

RESULTS

Endovascular embolization of AVM was impossible due to a risk of bilateral thalamic infarction and anatomical inaccessibility. Thalamic AVM was removed by high superior parietal approach without new neurological symptoms.

CONCLUSION

The first case of thalamic AVM fed by AOP originating from the contralateral posterior cerebral artery is reported. Surgical removal of AVM would be at the heart of treatment in order to avoid bilateral thalamic infarction.