Bifocal germ cell tumor of pineal germinoma and neurohypophyseal embryonal carcinoma: illustrative case

BACKGROUND

Bifocal germ cell tumors, with primarily identical tissue composition, occur concurrently in the neurohypophyseal and pineal regions.

OBSERVATIONS

A 16-year-old male patient exhibited increased intracranial pressure symptoms, with concurrent tumors in the pineal and neurohypophyseal regions, causing obstructive hydrocephalus. His serum human chorionic gonadotropin level was elevated, measuring 506.6 mIU/mL. Upon gross endoscopic examination, the pineal tumor appeared white, whereas the neurohypophyseal tumor appeared red and hemorrhagic. Because of the limited sample size of the latter, a frozen section biopsy was feasible only for the pineal lesion, which indicated the presence of a germinoma. Subsequently, carboplatin and etoposide were administered, resulting in the reduction of the pineal tumor, but no effect was observed in the neurohypophyseal tumor. Histopathological analysis confirmed the pineal lesion as a germinoma, whereas the neurohypophyseal lesion was an embryonal carcinoma. Thus, the treatment was altered to ifosfamide, carboplatin, and etoposide (ICE), leading to a response in both tumors. The patient underwent three additional cycles of ICE therapy and high-dose chemotherapy, followed by whole craniospinal irradiation, achieving complete remission.

LESSONS

Although most bifocal germ cell tumors share the same histological tissue, occasional differences may arise, necessitating separate biopsies for accurate assessment.

Gender Differences in the Cortical Distribution of Corpus Callosum Fibers

Introduction Research on gender-based disparities in human brain structure has spanned over a century, yielding conflicting results and ongoing debate. While some studies indicate minimal distinctions, others consistently highlight differences in the corpus callosum (CC), even after accounting for average brain size. Methods Diverging from previous approaches, this study examines the morphology of the entire CC fiber rather than solely focusing on its midsagittal structure. Utilizing advanced neuroimaging techniques and generalized Q-imaging tractography, CC streamlines were constructed to assess gender differences in fractional anisotropy (FA), volume ratio, and cortical distribution. Student's t-test was employed to examine the disparities in FA between gender groups, while gender-based distinctions in the normalized volume of the CC and its segments were assessed using analysis of covariance (ANCOVA), with absolute whole white matter volume serving as a covariate. Results No significant gender-based disparities were found in either FA or normalized CC volume. While females exhibited consistently larger normalized volume CC streamlines than males, these differences lost statistical significance after adjusting for absolute total white matter volume as a covariate. Nonetheless, CC streamlines in females displayed a broader spatial distribution, encompassing various cortical regions, including the bilateral prefrontal cortex (medial and lateral surfaces), as well as medial parietal and temporal regions. Conclusion This study elucidates gender-related variations in the morphology of the brain's white matter pathways, indicating a more widespread cortical distribution of CC fibers in females compared to males. However, the study underscores the need for further investigations into connectivity patterns to fully elucidate these gender-based disparities.

Current progress in genomics and targeted therapies for neurofibromatosis type 2

Neurofibromatosis type 2 (NF2), a multiple neoplasia syndrome, is a manifestation of an impaired expression of the merlin protein, exerting inhibitory effects on cell proliferation signals due to abnormalities of the NF2 gene located on chromosome 22. About half of patients inherit a germline mutation from a parent, and nearly 60% of de novo NF2 patients are estimated to have somatic mosaicism. The development of technical methods to detect NF2 gene mutation, including targeted deep sequencing from multiple tissues, improved the diagnostic rate of mosaic NF2. With improved understanding of genetics and pathogenesis, the diagnostic criteria for NF2 were updated to assist in identifying and diagnosing NF2 at an earlier stage. The understanding of cell signaling pathways interacting with merlin has led to the development of molecular-targeted therapies. Currently, several translational studies are searching for possible therapeutic agents targeting VEGF or VEGF receptors. Bevacizumab, an anti-VEGF monoclonal antibody, is widely used in many clinical trials aiming for hearing improvement or tumor volume control. Currently, a randomized, double-masked trial to assess bevacizumab is underway. In this randomized control trial, 12 other Japanese institutions joined the principal investigators in the clinical trial originating at Fukushima Medical University. In this review, we will be discussing the latest research developments regarding NF2 pathophysiology, including molecular biology, diagnosis, and novel therapeutics.

A Collision Tumor of Pit-1/SF-1-positive Double Pituitary Adenoma and a Craniopharyngioma Coexisting with Graves' Disease

Double or multiple pituitary adenomas expressing different types of transcription factors and collision tumors of pituitary adenomas and craniopharyngiomas are rare. In this report, we present a case of pituitary adenoma of two different cell populations, Pit-1 and SF-1, and an adenoma and craniopharyngioma collision tumor with coexisting Graves' disease. The patient had a 16-mm pituitary tumor with pituitary stalk calcification and optic chiasm compression but no visual dysfunction. Based on hormonal profile results, the tumor in the sella was considered a nonfunctioning pituitary adenoma; nevertheless, the pituitary stalk was invaded by a different lesion, which was later confirmed to be a craniopharyngioma. Using an endoscopic endonasal approach, the pituitary adenoma was removed; however, a small remnant remained medial to the right cavernous sinus. Because the pituitary stalk lesion was isolated from the pituitary adenoma, it was preserved to maintain pituitary function. Three years after the initial surgery, the patient suffered from Graves' disease and was treated with antithyroid medications. However, the intrasellar residual and pituitary stalk lesions gradually increased in size. A second surgery was performed, and the residual intrasellar and stalk lesions were completely removed. As per the initial and second histopathologies, the pituitary adenoma comprised different cell groups positive for thyroid-(TSH) and follicle-stimulating hormones, and each cell group was positive for Pit-1 and SF-1. The pituitary stalk lesion was an adamantinomatous craniopharyngioma. We believe that TSH-producing adenoma was involved in the development of Graves' disease or that treatment for Graves' disease increased TSH-producing adenoma.

Mechanical Thrombectomy for Acute Ischemic Stroke Caused by Prosthetic Aortic Valve Endocarditis Due to Exophiala dermatitidis Infection: A Case Report

Prosthetic valve endocarditis (PVE) can cause large cerebral vessel occlusion. Many reports suggested that mechanical thrombectomy (MT) is effective and useful for early diagnosis from the histopathological findings of thrombus. We present the case of a 62-year-old man, with a history of prosthetic aortic valve replacement and pulmonary vein isolation for his atrial fibrillation, who developed a high fever and an acute neurological deficit, with left hemiplegia and speech disorder. He was diagnosed as having an acute right middle cerebral artery embolism and underwent an MT. The embolic source was found to be a PVE vegetation. However, histopathological analysis of the thrombus could not detect the actual diagnosis. Although he was treated for bacterial endocarditis, his blood culture revealed a rare fungal infection with Exophiala dermatitidis not until >3 weeks after admission. Subsequently, a ß-D-glucan assay also indicated elevated levels. Although he underwent an aortic valve replacement on day 36, MRI showed multiple minor embolic strokes till that day. Early diagnosis of fungal endocarditis and detection of the causative pathogen are still challenging, and the disease has a high risk of occurrence of early and repeated embolic stroke. In addition to clinical findings and pathological studies, ß-D-glucan assay might be a good tool for the diagnosis and evaluation of fungal endocarditis.

A Ruptured Spetzler and Martin Grade V Arteriovenous Malformation in a Child Treated With Radiotherapy Followed by Embolization: A Case Report and Literature Review

Treatment of ruptured high-grade Spetzler-Martin (S&M) arteriovenous malformation (AVM) is challenging and requires a multidisciplinary treatment approach. Here, we report a case of ruptured giant callosal Grade V AVM in a child initially treated with stereotactic radiotherapy followed by endovascular embolization with Onyx; a management approach recently described in a few reports on the “postradiosurgical embolization” method. Complete obliteration was achieved 20 months after stereotactic radiotherapy and embolization. In this article, we discuss the usefulness and significance of postradiosurgical embolization, particularly for high-grade AVMs. To our knowledge, this is the first case with a giant Spetzler-Martin Grade V AVM treated with a postradiosurgical embolization method.

Intraoperative transcranial facial motor evoked potential monitoring in surgery of cerebellopontine angle tumors predicts early and late postoperative facial nerve function

OBJECTIVE

We propose a novel method that predicts facial nerve function (FNF) calculated from the drop and recovery of facial motor evoked potential (FMEP) amplitude ratio during the surgery of cerebellopontine angle tumors.

METHODS

We enrolled 73 patients with cerebellopontine angle tumor, and used a biphasic, constant current, and suprathreshold stimulation (BCS) protocol to record FMEP of the orbicularis oris. We measured the intraoperative minimum-to-baseline amplitude ratio (MBR), the final-to-baseline amplitude ratio (FBR), and the recovery value (RV). RV was measured by subtracting MBR from FBR. Using those values, we evaluated FNF both at early postoperative (EP) and late postoperative (LP) periods.

RESULTS

We successfully obtained 62 FMEP readings. Facial palsies occurred in 22 patients during the EP period, and 14 patients recovered during the LP period. Both MBR and FBR showed a significant correlation with FNF in the EP period. RV showed a good predictive power of FNF recovery during the LP period for the first time.

CONCLUSIONS

RV is a new and useful predictor of FNF recovery. MBR can be an intraoperative predictor of FNF in the EP period.

SIGNIFICANCE

FNF outcome in the early and late postoperative periods can be predicted by FMEP.

Rationale and Design of BeatNF2 Trial: A Clinical Trial to Assess the Efficacy and Safety of Bevacizumab in Patients with Neurofibromatosis Type 2 Related Vestibular Schwannoma

Simple Summary

Neurofibromatosis type 2 (NF2) is a rare genetic hereditary disease characterized by multiple central nervous system tumors, most frequently bilateral vestibular schwannomas (VSs). No chemotherapeutic agents are available for clinical use, and surgery and radiotherapy are the only therapeutic options available now. Still, neither treatment option alleviates hearing loss in patients with NF2 and VS; they may even exacerbate it. However, bevacizumab has been reported to be effective in suppressing the tumor’s growth and has shown unprecedented efficacy in improving hearing. We describe a new ongoing and novel clinical trial, BeatNF2, a randomized, double-blinded, placebo-controlled, multicenter trial to assess bevacizumab’s efficacy and safety in patients with NF2. The study’s primary endpoint is improved hearing function 24 weeks after the beginning of the treatment protocol.

Abstract

Neurofibromatosis type 2 (NF2) causes bilateral vestibular schwannomas (VSs), leading to deafness. VS is treated by surgery or radiation, but neither treatments prevent hearing loss. Bevacizumab was found to be effective in suppressing the tumor’s growth and may help to improve hearing. We are conducting a randomized, double-blind, multicenter clinical trial to verify the efficacy and safety of bevacizumab in NF2-related VS. The primary objective is to evaluate the efficacy of bevacizumab in improving hearing in the affected ear. One of the secondary objectives is to evaluate bevacizumab’s efficacy in rechallenge treatment in relapsed cases. Sixty patients will randomly receive either bevacizumab or a placebo and will be clinically observed for 48 weeks in the initial intervention phase. In the first half (24 weeks), they will receive either 5 mg/kg of bevacizumab or a placebo drug. In the second half, all patients will receive 5 mg/kg of bevacizumab. If hearing function deteriorated in a patient who had shown improvement during the first phase, a rechallenge dose with bevacizumab would be offered.

Secondary brain tumors after cranial radiation therapy: A single-institution study

Aim

To study the probability of developing secondary brain tumors after cranial radiotherapy.Background Patients treated with cranial radiotherapy are at risk for developing secondary brain tumors.

Patients and methods

We planned an institutional survey for secondary brain tumors in survivors after cranial irradiation and reviewed the 30-year duration data. Event analysis and cumulative proportion curves were performed to generally estimate the cumulative proportion of developing secondary brain tumors, cavernoma and meningioma at different periods of time.

Results

Secondary brain tumors occurred in 21% of cases: 10% were cavernomas, 6% were meningiomas, 3% were skull osteomas, and 1% were anaplastic astrocytoma. The cumulative proportion of developing secondary brain tumor was 6% at 10 years and 20% at 20 years, while the cumulative proportion for developing cavernomas and meningiomas was 16% and 7% at 20 years, respectively.

Conclusion

Our study shows that patients who received cranial irradiation were at risk of secondary brain tumors such as cavernomas and meningiomas. Thus, a meticulous follow-up of cancer survivors with history of cranial irradiation by an annual MRI scan is justifiable. This will help clinicians to detect secondary brain tumors early and make its management much easier.

Acute paradoxical brain herniation after decompressive craniectomy for severe traumatic brain injury: A case report

Background:

Sinking skin flap syndrome or paradoxical brain herniation is an uncommon neurosurgical complication, which usually occurs in the chronic phase after decompressive craniectomy. We report a unique case presenting with these complications immediately after decompressive craniectomy for severe traumatic brain injury.

Case Description:

A 65-year-old man had a right acute subdural hematoma (SDH), contusion of the right temporal lobe, and diffuse traumatic subarachnoid hemorrhage with midline shift to the left side. He underwent an emergency evacuation of the right SDH with a right decompressive frontotemporal craniectomy. Immediately after the operation, his neurological and computed tomography (CT) findings had improved. However, within 1 h after the surgery, his neurological signs deteriorated. An additional follow-up CT showed a marked midline shift to the left, i.e., paradoxical brain herniation, and his skin flap overlying the decompressive site was markedly sunken. We immediately performed an urgent cranioplasty with the right temporal lobectomy. He responded well to the procedure. We suspected that a cerebrospinal fluid leak had caused this phenomenon.

Conclusion:

Decompressive craniectomy for severe traumatic brain injury can lead to sinking skin flap syndrome and/or paradoxical brain herniation even in the acute phase. We believe that immediate cranioplasty allows the reversal of such neurosurgical complications.

Role of transcranial sphenoidotomy in skull base surgery: classification of surgical techniques based on the surgical anatomy of the sphenoid sinus

OBJECTIVE

Although sphenoidotomy is more commonly performed via the transnasal approach than via the transcranial approach, transcranial sphenoidotomy (TCS) remains indispensable for en bloc resection of locally advanced sinonasal malignant tumors (SNMTs) extending to the skull base. TCS also enables transsphenoidal transposition of the temporoparietal galeal flap (TPGF) to compensate for the lack of vascularized reconstructive tissue after endoscopic transnasal skull base surgery. The objective of this study was to review the authors' surgical experience using TCS with an emphasis on the surgical anatomy of the sphenoid sinus and on the purpose of TCS. Relevant anatomy is further illustrated through cadaveric dissection and photo documentation.

METHODS

The authors reviewed the records of 50 patients who underwent TCS at the Nagoya University Hospital, Fukushima Medical University Hospital, or Aichi Medical University Hospital over the course of 7 years (between January 2011 and November 2017). The authors also performed cadaveric dissection in 2 adult cadaveric skull base specimens.

RESULTS

Of the 50 patients included in this study, 44 underwent craniofacial resection (CFR) for en bloc resection of SNMTs involving the anterior and/or lateral skull base, and 6 underwent transsphenoidal transposition of the TPGF flap. The authors categorized the TCS procedures according to the portion of the sphenoid sinus wall involved (i.e., superior, lateral, and superolateral). Superior sphenoidotomy was used in patients requiring anterior CFR. Lateral sphenoidotomy was further divided into 2 subtypes, with type 1 procedures performed for the transsphenoidal transpositioning of the TPGF, and type 2 procedures used in patients requiring lateral CFR. Superolateral sphenoidotomy was used in anterolateral CFR.

CONCLUSIONS

TCS still represents a useful tool in the armamentarium of neurosurgeons treating central skull base lesions. The newly proposed surgical classification facilitates a profound understanding of TCS and how to incorporate this technique into clinical practice.

A Novel Intraoperative Laser Light Imaging System to Simultaneously Visualize Visible Light and Near-Infrared Fluorescence for Indocyanine Green Videoangiography

Background

Intraoperative indocyanine green videoangiography (ICG-VA) has been reported to be utilized in various cerebrovascular surgeries, wherein the blood flow is noticeably shown in white with a black background. ICG flow alone, but not other structures, can be observed using ICG-VA. We developed a novel high-resolution intraoperative imaging system using laser light source for simultaneously visualizing both visible light and near-infrared (NIR) fluorescence images of ICG-VA.

Methods

We used a novel system for 14 cerebrovascular cases. The operative field was illuminated via an operating microscope using a novel laser light source with four bands at 464 (blue), 532 (green), 640 (red), and 785 nm (NIR region). The observed light from the operative field was split using a beam splitter cube into visible (420– 660 nm) and NIR fluorescence emission light (832–900 nm). Images from the color video and NIR fluorescence emission windows were merged for visualization on a monitor screen simultaneously. Laser light was compared with xenon light, and both setups were tested for cerebrovascular surgeries.

Results

Laser light has numerous advantages over xenon light. The present setup clearly visualized the color operative field with enhanced blood flow. Complete clipping or incomplete clipping with neck remnant or remnant flow into an aneurysm was confirmed in aneurysm surgeries. Feeding arteries and draining veins were easily distinguished in case of arteriovenous malformation.

Conclusions

Using the present setup, we can observe the color operative field and enhanced blood flow using ICG in real time. This setup could facilitate various cerebrovascular surgeries.

Palliative shunt surgery for patients with leptomeningeal metastasis

OBJECTIVES

Leptomeningeal metastasis (LM) is associated with poor prognosis and affects the quality of life (QOL) of end-stage cancer patients. Severe headache associated with hydrocephalus causes reduced QOL. We investigated the clinical value of surgical treatment for hydrocephalus in LM patients.

PATIENTS AND METHODS

The medical records of 11 consecutive patients who underwent lumboperitoneal shunt (LPS) or ventriculoperitoneal shunt (VPS) at our institution between 2007 and 2016 were investigated. Primary brain tumor patients were excluded. We assessed the neurological status and therapeutic effects at 1 month after the shunt surgery.

RESULTS

The patients were three males and eight females with a median age of 58 years (interquartile range [IR] 52-68 years). The median preoperative neutrophil-to-lymphocyte ratio was 6.4 (IR 4.8-9.2). Symptom improvement was observed in nine patients, and severe headache was relieved in seven (88%) out of eight patients. The median Karnofsky performance status scale increased from 40 to 60, and the median overall survival after primary malignancy diagnosis was 27.4 months (IR 19.6-63.1 months). The median survival after the diagnosis of brain parenchymal metastasis, LM, and shunt surgery were 7.2 months (IR 5.1-14.1 months), 3.9 months (IR 3.5-6.3 months), and 3.3 months (IR 2.9-5.7 months), respectively.

CONCLUSION

Shunt surgery for hydrocephalus could offer an effective palliative surgical option for symptom relief especially relief of severe headache, contributing improvement of QOL in LM patients.

Guanidinium chloride-induced spectral perturbations of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid confound interpretation of data on molten globule states

We describe limitations in the use of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) to examine unfolding intermediates associated with guanidinium chloride (GuHCl)-induced protein denaturation. Several studies have used alterations in fluorescence emission of bis-ANS to quantify the population of "molten globule" states. Our findings indicate that the observed changes in bis-ANS spectroscopic properties could originate from the interactions of bis-ANS and GuHCl and the aggregation of the dye at higher GuHCl concentrations. We posit that in the absence of additional complementary structural or spectroscopic measurements, the use of bis-ANS emission alone to monitor protein conformations can be misleading.

Ovarian steroids modulate gonadotropin-releasing hormone-induced biphasic luteinizing hormone secretory responses and inositol phosphate accumulation in rat anterior pituitary cells and alpha T3-1 gonadotrophs

The ovarian steroids estradiol and progesterone act as important modulators of GnRH-induced luteinizing hormone (LH) secretion from anterior pituitary cells. Recently, we demonstrated that the steroids are able to influence GnRH-stimulated Ca2+ mobilization from extra- and intracellular sources. Here we investigated the actions of estradiol and progesterone on GnRH-induced biphasic LH secretory responses in the model of perifused female rat pituitary cells. A 20 min GnRH stimulus elicited biphasic LH responses composed of an initial peak followed by a prolonged plateau phase. Both phases were equally enhanced by long-term (48 h) estradiol treatment. This action was facilitated by subsequent short-term progesterone treatment. In contrast, combined treatment with estradiol and progesterone for 48 h led to inhibited LH secretory profiles. To determine the steroid actions on the extracellular Ca2+ independent component of LH secretion we performed experiments using cells that were perifused with Ca2+ deficient medium. Under these conditions the cells responded exclusively with a single peak phase of LH secretion, which was augmented or inhibited by estradiol and progesterone treatment as described above. To test the hypothesis that an effect of estradiol and progesterone on GnRH-induced polyphophoinositide hydrolysis is responsible for their modulatory actions on Ca2+ signals and LH secretion we measured inositol phosphate (IP) accumulation after different steroid treatment paradigms in rat pituitary cells and alpha T3-1 immortalized gonadotrophs. GnRH-induced IP production was enhanced by long-term estradiol treatment. Short-term exposure of estradiol-primed cells to progesterone did not lead to significant changes of IP production. The long-term progesterone treatment paradigm enhanced GnRH-induced IP formation, while it decreased Ca2+ signals and LH secretion. Alpha T3-1 cells were used to perform more detailed analysis of IP formation. The actions of estradiol and progesterone on the production of inositol mono-, bis-, and trisphosphates were similar to those observed in the mixed cell population. It is concluded that estradiol and progesterone modulate both peak and plateau phases of GnRH-stimulated LH secretory responses, effects which are associated with their impact on Ca2+ signals. Our findings argue against a role of IP modulation in the mechanism of progesterone actions on Ca2+ signaling and LH secretion in gonadotrophs. Such a mechanism might be involved in the positive effects of estradiol in these cells.