Pitfalls of Neuroendoscopic Biopsy of Intraventricular Germ Cell Tumors

A case of a pineal parenchymal tumor of intermediate differentiation with bifocal lesions differentiated by negative placental alkaline phosphatase in the spinal fluid

Placental alkaline phosphatase (PLAP) in the spinal fluid is helpful for the diagnosis of intracranial germinomas. Bifocal lesions involving the pineal and pituitary regions have also been reported as characteristic findings of intracranial germinomas. We present a rare case of a 15-year-old boy with a pineal parenchymal tumor of intermediate differentiation (PPTID) with bifocal lesions negative for PLAP. Magnetic resonance imaging of the brain revealed bifocal mass lesions in the pineal and suprasellar regions and non-communicating hydrocephalus. We initially suspected a germinoma based on imaging findings, but all tumor markers, including PLAP, in the spinal fluid were negative. Based on these results, germinoma was considered less likely, and an endoscopic third ventriculostomy and endoscopic tumor biopsy were performed for diagnosis. The histopathological diagnosis was PPTID, corresponding to World Health Organization grade 3, in both pineal and suprasellar specimens. A craniotomy for tumor removal was performed, resulting in total resection. PLAP is known to have high sensitivity and extremely high negative predictive value for germinomas. Although bifocal lesions highly suggest germ cell tumors, there are exceptions, as in the present case. This case suggests that PLAP measurements are useful for differentiation, leading to appropriate treatment strategies.

Intraventricular Tumors: Surgical Considerations in Lateral and Third Ventricular Tumors

Management of lateral and third ventricular tumors has been a challenge for neurosurgeons. Advances in imaging and pathology have helped in a better understanding of the treatment options. Technical refinement of microsurgical technique and addition of endoscopy has enabled more radical excision of tumors, when indicated, and added more safety.A proper understanding of the pathology at various ages and treatment options is continuously evolving. Many pediatric tumors are amenable to conservative surgical methods with effective complementary treatments. However, radical surgery is required in many adults as the main treatment and for many benign tumors. Various intraventricular lesions encountered and their surgical management is reviewed here for their efficacy, safety, and outcome, encompassing changes in our practice over the last 20 years.

Results of the treatment of pineal tumors in children: the Lyon experience

INTRODUCTION

Pineal tumors are rare and their incidence is of 1% among all pediatric tumors of the central nervous system. Patient survival depends on the histology, the extension of the surgical removal, and the efficacy of the complementary treatment (chemotherapy and cranio-spinal irradiation), as well as the age of the patient.

MATERIALS AND METHODS

In this study, we analyzed 151 pediatric patients treated for pineal tumors from 1997 to 2020 in Lyon, France. All patients were recorded in the French Register of Pineal tumors, which has been centralized and maintained in Lyon since 2010.

RESULTS

Our analysis shows that benign tumors have an overall positive prognosis with total surgical removal. Concerning pineal parenchymal tumors, pinealoblastomas have a poor prognosis , especially in children less than three years old. A new pathological classification system allows for a better stratification of patient risk within different groups of patients with pineal tumors. It is also important to note that the identification of DICER 1 syndrome in families with pinealoblastomas warrant further medical investigation. Patients with Germ Cell Tumors have more favorable outcomes, with a global survival rate of 87 % and a pure germinoma survival rate of almost 97%. When analyzing the prognosis of pineal gland gliomas, otherwise known as tectal plate gliomas, pilocytic astrocytomas had a promising prognosis. Otherwise, prognosis of other tectal plate gliomas are related to the grade of malignancy and the efficacy of complementary treatment. Lastly, papillary tumors need a complete removal for the best chance of survival, and Atypical teratoid/ rabdoid tumors (AT/TR) still have a bad prognosis, regardless of surgical resection.

CONCLUSIONS

Our results show that, with regards to pediatric pineal region tumors, there are still areas in prognostic indicators that need to be improved. Similarly, these pathologies need to be treated via a multidisciplinary approach to improve a patient's survival rate and their quality of life.

Neuroendoscopy in the management of pineal region tumours in children

INTRODUCTION

Pineal region tumours (PRTs) are more common in children and represent a wide variety of lesions. The practise of a radiation test dose is obsolete and a biochemical/histological diagnosis is recommended before further therapy. Many patients present with hydrocephalus. Advances in neuroendoscopic techniques have allowed safe and effective management of this obstructive hydrocephalus with an opportunity to sample cerebrospinal fluid (CSF) and obtain tissue for histopathology. Definitive surgery is required in less than a third. Endoscopic visualisation and assistance is increasingly used for radical resection, where indicated.

METHODOLOGY

Our experience of endoscopic surgery for paediatric PRTs from 2002 to 2021 is presented. All patients underwent MRI with contrast. Serum tumour markers were checked. If negative, endoscopic biopsy and endoscopic third ventriculostomy (ETV) were performed; and CSF collected for tumour markers and abnormal cells. For radical surgery, endoscope-assisted microsurgery procedures were performed to minimise retraction, visualise the extent of resection and confirm haemostasis.

RESULTS

M:F ratio was 2:1. The median age of presentation was 11 years. Raised ICP (88.88%) was the commonest mode of presentation. Nineteen patients had pineal tumours, one had a suprasellar and pineal tumour, one had disseminated disease, while six had tectal tumours. The ETB diagnosis rate was 95.45%, accuracy rate was 83.3% and ETV success rate was 86.96%.

CONCLUSION

Neuroendoscopy has revolutionised the management of paediatric PRTs. It is a safe and effective procedure with good diagnostic yield and allows successful concurrent CSF diversion, thereby avoiding major surgeries and shunt implantation. It is also helpful in radical resection of lesions, where indicated.

Intracranial Germinomas: Diagnosis, Pathogenesis, Clinical Presentation, and Management

PURPOSE OF REVIEW

Intracranial germinomas constitute a rare brain tumor entity of unknown etiology, characterized by unique histopathology and molecular biology. In this manuscript, we review the literature focusing on the epidemiology, histopathology with molecular biology, clinical presentation with emphasis on tumor location, diagnostic workup, and current treatment strategies with related clinical outcomes of intracranial germinomas.

RECENT FINDINGS

Although the optimal treatment strategy remains a matter of debate, intracranial germinomas respond well to radiotherapy, chemotherapy, or a combination of both and are characterized by very high cure and survival rates. It is well-known that early discrimination of germinomas from other intracranial neoplasms facilitates the timely initiation of appropriate treatment, thereby contributing to the reduction of morbidity as well as mortality. Ongoing research will need to be directed towards discovering and refining reliable parameters for early diagnosis and evaluation of prognosis in patients with intracranial germinomas.

Diagnosis and Management of Pineal Germinoma: From Eye to Brain

Pineal germinomas can be very complex in terms of presentation, diagnosis, and management. This review attempts to simplify this complexity in an organized manner, addressing the anatomic relationships that provide the basis for the uniqueness of pineal germinoma. Ocular findings and signs and symptoms of elevated intracranial pressure are the keys to suspecting the diagnosis and obtaining the necessary imaging and cerebrospinal fluid studies. Other symptoms can suggest spread beyond the pineal region. Surgery may only be needed to obtain tissue for a definitive diagnosis, as germinoma is highly responsive to chemotherapy and focused radiation therapy. Hydrocephalus, usually related to tumor obstruction of the cerebral aqueduct, may also need to be addressed. Outcome for pineal germinoma is usually excellent, but relapse can occur and may require additional intervention. These issues are detailed in this review.

Outcome of endoscopic transcortical intraventricular biopsy of isolated thickened pituitary stalk lesions in children

OBJECTIVE

The purpose of this study was to investigate the efficacy and safety of endoscopic transcortical intraventricular biopsy in pediatric patients with isolated thickened pituitary stalk lesions.

METHODS

From 1994 to 2018, 16 pediatric patients (8 males and 8 females) underwent endoscopic transcortical intraventricular biopsy at a single institution to establish an accurate pathological diagnosis for appropriate treatment strategies.

RESULTS

Preoperatively, the median diameter of the pituitary stalks was 5.31 ± 1.67 mm (range 3.86-9.17 mm). Overall, the diagnostic yield at endoscopic intraventricular biopsy was 93.8%. Histopathological diagnosis included germinoma (n = 10, 62.5%), Langerhans cell histiocytosis (n = 4, 25%), pilocytic astrocytoma (n = 1, 6.3%), and pituicytoma (n = 1, 6.3%). Two patients developed new diabetes insipidus after the procedure, and 3 patients had new postoperative hypothyroidism. There were no postoperative neurological deficits in this series.

CONCLUSIONS

Neuroendoscopic biopsy via the transcortical intraventricular corridor was shown to be safe and to aid in a reliable histopathological diagnosis in the management of isolated pituitary stalk lesions in pediatric patients. It can be considered a minimally invasive alternative to open biopsy via transcranial or endonasal corridors.

The Japan Society for Neuro-Oncology Guideline on the Diagnosis and Treatment of Central Nervous System Germ Cell Tumors

Primary CNS germ cell tumors (GCTs) are rare neoplasms predominantly observed in the pediatric and young adult populations. In line with the hypothesis that the primordial germ cell is the cell-of-origin, histopathological examinations for this pathology involve a diverse range of components mirroring the embryogenic developmental dimensions. Chemotherapy and radiotherapy are the mainstays of treatment, with surgery having a limited role for diagnosis and debulking of residual tissue after treatment. While better management has been achieved over recent decades by modifying radiation coverage and selecting appropriate chemotherapy, standardization of treatment remains challenging, partly due to the low volume of cases encountered in each institution. As the incidence is higher in East Asia, including Japan, the Japan Society for Neuro-Oncology established a multidisciplinary task force to create an evidence-based guideline for CNS GCTs. This guideline provides recommendations for multiple dimensions of clinical management for CNS GCTs, with particular focus on diagnostic measures including serum markers, treatment algorithms including surgery, radiotherapy and chemotherapy, and under-investigated but important areas such as treatment for recurrent cases, long-term follow-up protocols and long-term sequelae. This guideline serves the purpose of helping healthcare professionals keep up to date with current knowledge and standards of management for patients with this rare disease in daily clinical practice, as well as driving future translational and clinical research by recognizing unmet needs concerning this tumor.

Prognosticating survival of pineal parenchymal tumors of intermediate differentiation (PPTID) by grade

BACKGROUND

Pineal parenchymal tumors of intermediate differentiation (PPTID) are a rare group of pineal parenchymal tumors classified by histology as either World Health Organization (WHO) Grades 2 or 3. The rarity of these tumors in adults has left a number of clinical management questions open. Correspondingly, the aim of this study was to aggregate a large PPTID cohort with sufficient statistical power from a large national cancer database to analyze prognostic parameters.

METHODS

All PPTID patients aged over 18 years in the U.S. National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Data were summarized and survival was modeled using Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 103 adult PPTID patients were identified in the NCDB with 63 (61%) WHO Grade 2 and 40 (39%) WHO Grade 3 tumors. Overall, mean age was 53 ± 18 years with even gender distribution. A total of 75 (73%) patients underwent surgical resection for diagnosis, with gross total resection (GTR) was the most common resection outcome in 50/75 (67%). Chemotherapy was utilized in 18 (17%) patients, and radiation therapy in 37 (36%) patients. Overall, 5-year survival rate was estimated to be 54% (95% CI 42-64%), with mean survival was 84 (95% CI 69-99) months. Patients with Grade 2 tumors survived statistically longer than Grade 3 tumor counterparts (P < 0.01). Overall, older age (HR 1.09, P < 0.01) was associated with shorter survival, whereas GTR (HR 0.43, P = 0.02) was associated with longer survival. Both these parameters were significant within Grade 2 and Grade 3 subgroup analyses as well.

CONCLUSIONS

PPTID are rare tumors with expected mean survival more than 5 years, although Grade 2 tumors are expected to survive longer than Grade 3 tumors. Age and gross total resection are significant independent predictors of survival in PPTID overall, as well as within Grade 2 and Grade 3 subgroups separately. The prognostic role and benefit of adjuvant therapy is yet to be elucidated, mandating more molecular and biologic research be done to further optimize clinical management in the future.

Cytologic Features of Ventricular Tumors of the Central Nervous System: A Review with Emphasis on Diff-Quik Stained Smears

BACKGROUND

Neoplasms from the ventricular system share a common location but have highly variable histogenesis. Many are slowly growing tumors that behave in a benign fashion. They can be classified as primary and secondary tumors. The most common primary tumors are ependymomas, subependymomas, subependymal giant cell astrocytomas, central neurocytomas, choroid plexus tumors, meningiomas, germinomas, pineal parenchymal tumors, papillary tumors of the pineal region, chordoid gliomas, rosette-forming glioneuronal tumors of the fourth ventricle, and craniopharyngiomas. Pilocytic astrocytomas, medulloblastomas, and atypical teratoid/rhabdoid tumors often show secondary involvement of the ventricular system.

SUMMARY

Advances in neurosurgery have facilitated access to the ventricular system increasing the number of cases in which such tumors can be biopsied. In this context, cytology has been proven to be an extremely useful diagnostic tool during intraoperative pathologic consultations. Many ventricular tumors are infrequent, and the cytologic information available is limited. In this review, we describe the cytologic features of the uncommon ventricular tumors and report on unusual findings of the more common ones. For the cytologic evaluation of brain tumors, many neuropathologists prefer formalin fixation and hematoxylin and eosin staining. In this review, we highlight the cytologic findings as seen with Diff-Quik, a very popular staining method among cytopathologists. In fact, when pathologists are unfamiliar with cytology, it is common to request the assistance of cytopathologists during the evaluation of intraoperative procedures. Key Message: Ventricular tumors of the central nervous system comprise a group of heterogeneous tumors with very different cytologic features. The cytomorphology of these tumors, including rare entities, is often very characteristic, allowing a precise recognition during intraoperative pathologic consultations. Diff-Quik is a valuable staining method that can be used alone or as a complement to hematoxylin and eosin staining. Diff-Quik allows for clear visualization of the overall architecture, cytoplasmic details, and extracellular material.

Detecting non-germinomatous germ cell tumor component by arterial spin labeling perfusion-weighted MR imaging in central nervous system germ cell tumor

PURPOSE

Differentiating between germinoma and non-germinomatous germ cell tumor (NGGCT) is important because sensitivity to chemotherapy and/or radiotherapy is quite different between these two subgroups. In this study, we evaluated whether the arterial spin labeling (ASL) based perfusion-weighted imaging (PWI) could provide additional information for the differential diagnosis between germinoma and NGGCT.

METHOD

Between 2011 and 2018, 20 patients with central nervous system (CNS) germ cell tumor (GCT) who underwent preoperative MR imaging including ASL-PWI were enrolled in this study. Relative tumor blood flow (rTBF) was evaluated on ASL-PWI by manually placing regions of interest at gadolinium enhanced part of the tumors and normal subcortical white matter. Presence of intratumoral T1 hyperintense foci and apparent diffusion coefficient (ADC) were also evaluated. The final diagnosis was made by the combination of tumor markers and the histological diagnosis.

RESULTS

Among 20 patients of CNS-GCT, 11 were diagnosed as germinoma and 9 were diagnosed as NGGCT. In the germinoma subgroup, the rTBF ranged from 0.90 to 1.71 (mean 1.21, median 1.09), while it ranged from 1.14 to 5.75 (mean 3.91, median 3.31) in NGGCT subgroup. The receiver operating characteristic (ROC) curve showed that calculating rTBF is useful for differentiating between germinoma and NGGCT (area under the curve (AUC) 0.929, P = 0.0012) compared to intratumoral T1 hyperintense foci (AUC 0.788, P = 0.0304) and ADC (AUC 0.919, P = 0.0016).

CONCLUSIONS

High rTBF obtained by ASL-PWI implied the presence of NGGCT component. This information might help in deciding the chemotherapy/radiotherapy intensity.

Cerebrospinal fluid ctDNA and metabolites are informative biomarkers for the evaluation of CNS germ cell tumors

Serum and cerebrospinal fluid (CSF) levels of α-fetoprotein and β-subunit of human chorionic gonadotropin are used as biomarkers for the management of central nervous system (CNS) germ cell tumors (GCTs). However, additional discriminating biomarkers are required. Especially, biomarkers to differentiate non-germinomatous germ cell tumors (NGGCTs) from germinomas are critical, as these have a distinct prognosis. We investigated CSF samples from 12 patients with CNS-GCT patients (8 germinomas and 4 NGGCTs). We analyzed circulating tumor DNA (ctDNA) in CSF to detect mutated genes. We also used liquid chromatography-mass spectrometry to characterize metabolites in CSF. We detected KIT and/or NRAS mutation, known as frequently mutated genes in GCTs, in 3/12 (25%) patients. We also found significant differences in the abundance of 15 metabolites between control and GCT, with unsupervised hierarchical clustering analysis. Metabolites related to the TCA cycle were increased in GCTs. Urea, ornithine, and short-chain acylcarnitines were decreased in GCTs. Moreover, we also detected several metabolites (e.g., betaine, guanidine acetic acid, and 2-aminoheptanoic acid) that displayed significant differences in abundance in patients with germinomas and NGGCTs. Our results suggest that ctDNA and metabolites in CSF can serve as novel biomarkers for CNS-GCTs and can be useful to differentiate germinomas from NGGCTs.

Management of pineal region tumors in a pediatric case series

Pineal region tumors commonly present with non-communicating hydrocephalus. These heterogeneous histological entities require different therapeutic regimens. We evaluated our surgical experience concerning procurance of a histological diagnosis, management of hydrocephalus, and choice of antitumoral treatment. We analyzed the efficacy of neuroendoscopic biopsy and endoscopic third ventriculocisternostomy (ETV) in patients with pineal region tumors between 2006 and 2019 in a single-center retrospective cross-sectional study with regard to diagnostic yield, hydrocephalus treatment, as well as impact on further antitumoral management. Out of 28 identified patients, 23 patients presented with untreated hydrocephalus and 25 without histological diagnosis. One patient underwent open biopsy, and 24 received a neuroendoscopic biopsy with concomitant hydrocephalus treatment if necessary. Eighteen primary ETVs, 2 secondary ETVs, and 2 ventriculoperitoneal shunts (VPSs) were performed. Endoscopic biopsy had a diagnostic yield of 95.8% (23/24) and complication rates of 12.5% (transient) and 4.2% (permanent), respectively. ETV for hydrocephalus management was successful in 89.5% (17/19) with a median follow-up of more than 3 years. Following histological diagnosis, 8 patients (28.6%) underwent primary resection of their tumor. Another 9 patients underwent later-stage resection after either adjuvant treatment (n = 5) or for progressive disease during observation (n = 4). Eventually, 20 patients received adjuvant treatment and 7 were observed after primary management. One patient was lost to follow-up. Heterogeneity of pineal region tumor requires histological confirmation. Primary biopsy of pineal lesions should precede surgical resection since less than a third of patients needed primary surgical resection according to the German pediatric brain tumor protocols. Interdisciplinary decision making upfront any treatment is warranted in order to adequately guide treatment.

Placental alkaline phosphatase in cerebrospinal fluid as a biomarker for optimizing surgical treatment strategies for pineal region germ cell tumors

Pineal region germ cell tumors are a heterogenous group of tumors; of these, pure germinoma shows high sensitivity to adjuvant therapy, and the timing and sequence of surgical intervention and adjuvant/neoadjuvant therapy are important for devising a treatment strategy for intracranial germ cell tumors (IGCT). Biopsy is diagnostically useful, but is often insufficient because only a limited amount of specimen can be obtained. In the present study, we aimed to determine the value of cerebrospinal fluid placental alkaline phosphatase (PLAP) levels, reflecting the presence of germinoma, as a reliable indicator to determine treatment strategies for pineal germ cell tumors. To assess the relationship between elevated PLAP levels and the presence of germinoma, we retrospectively reviewed histopathological findings of 25 surgical cases of IGCT in the pineal region. The PLAP value reflects the existence of a germinoma component within a total tumor volume; consequently, tumor volume could be reduced in cases with elevated PLAP, while tumors negative for PLAP did not decrease in size. Therefore, PLAP levels may help neurosurgeons optimize surgical intervention timing for teratomas in the pineal region.

Regression of Pineal Lesions: Spontaneous or Iatrogenic? A Case Report and Systematic Literature Review

BACKGROUND

Tumors arising from the pineal region account for approximately 1% of intracranial neoplasms. We present a case of a previously healthy 5-year-old boy with an acute onset of headache. A magnetic resonance imaging (MRI) scan showed a pineal mass with aqueduct compression. The patient was scheduled for tumor resection. An endoscopic third ventriculostomy was performed in advance for the treatment of hydrocephalus. Afterwards, MRI showed a relevant regression of the pineal mass without specific treatment. Consequently, surgery was cancelled and further MRI follow-up showed a regression of the mass and a constant tumor mass over a period of 30 months. Spontaneous regression of malignant tumors is a rare phenomenon with an incidence of 1 of 60,000-100,000 cases. Only a few cases with spontaneous regression of pineal tumors have been reported.

METHODS

We performed a systematic literature review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines on spontaneously regressing pineal lesions and found 13 cases in the literature.

RESULTS

Six hypotheses for explaining tumor regression were found, comprising treatment with steroids, effects of diagnostic irradiation, treatment of hydrocephalus, pineal apoplexy, surgical trauma, and immunologic mechanisms. None of these mechanisms was evidentiary. However, in all reported cases, some kind of treatment (e.g. treatment of hydrocephalus, application of steroids, and so on) has been performed before tumor regression.

CONCLUSIONS

The clinician has to bear in mind that regression of pineal tumors might be triggered by use of steroids, for example, and in cases of improvement of the patient's presenting symptoms, new MRI scans should be performed.