A Cerebellar Tumor-to-Tumor Metastasis in a Patient With Von Hippel-Lindau Disease.

Tumor-to-tumor metastasis in the central nerve system is uncommon in our routine practice. Most reports include metastatic breast cancer into meningioma. Here we report a metastatic clear cell renal cell carcinoma (ccRCC) into a cerebellar hemangioblastoma in a patient with von Hippel-Lindau (VHL) disease. Imaging cannot distinguish metastatic ccRCC from primary cerebellar hemangioblastoma. Immuno-molecular studies are proven to be diagnostic. We also reviewed previously documented tumor-to-tumor metastasis of ccRCC to cerebellar hemangioblastoma in VHL disease. Lastly, we discussed potential mechanisms involved in the metastasis of ccRCC to hemangioblastoma in the cerebellum in patients with VHL.

Screening and surveillance recommendations for central nervous system hemangioblastomas in pediatric patients with Von Hippel-Lindau disease.

PURPOSE: Von Hippel-Lindau (VHL) disease is an autosomal-dominantly inherited tumor predisposition syndrome. One of the most common tumors are central nervous system (CNS) hemangioblastomas. Recommendations on the initiation and continuation of the screening and surveillance program for CNS tumors in pediatric VHL patients are based on small case series and thus low evidence level. To derive more robust screening recommendations, we report on the largest monocentric pediatric cohort of VHL patients. METHODS: We performed a retrospective analysis on a pediatric cohort of 99 VHL patients consulted at our VHL center from 1992 to 2023. Clinical, surgical, genetic, and imaging data were collected and statistically analyzed. RESULTS: 42 patients (50% male) developed CNS hemangioblastomas, of whom 18 patients (56% male) underwent hemangioblastoma surgery (mean age at first surgery: 14.9 ± 1.9 years; range 10.2-17). The first asymptomatic patient was operated on at the age of 13.2 years due to tumor progress. Truncating VHL mutation carriers had a significantly higher manifestation rate (HR = 3.7, 95% CI: 1.9-7.4, p < 0.0001) and surgery rate (HR = 3.3, 95% CI: 1.2-8.9, p = 0.02) compared with missense mutation carriers. CONCLUSION: We recommend starting MRI imaging at the age of 12 years with examination intervals every (1-) 2 years depending on CNS involvement. Special attention should be paid to patients with truncating variants. Affected families should be educated regularly on potential tumor-associated symptoms to enable timely MRI imaging and eventually intervention, as CNS hemangioblastoma may develop before screening begins. GERMAN CLINICAL TRIALS REGISTER REGISTRATION NUMBER: DRKS00029553, date of registration 08/16/2022, retrospectively registered.

Recurrent Tuberous Sclerosis Complex/Mammalian Target of Rapamycin Mutations Define Primary Renal Hemangioblastoma as a Unique Entity Distinct From Its Central Nervous System Counterpart.

ABSTRACT: Renal hemangioblastoma (HB) is a rare subset of HBs arising outside of the central nervous system (CNS), with its molecular drivers remaining entirely unknown. There were no significant alterations detected in previous studies, including von Hippel-Lindau gene alterations, which are commonly associated with CNS-HB. This study aimed to determine the real molecular identity of renal HB and better understand its relationship with CNS-HB. A cohort of 10 renal HBs was submitted for next-generation sequencing technology. As a control, 5 classic CNS-HBs were similarly analyzed. Based on the molecular results, glycoprotein nonmetastatic B (GPNMB) immunohistochemistry was further performed in the cases of renal HB and CNS-HB. Mutational analysis demonstrated that all 10 renal HBs harbored somatic mutations in tuberous sclerosis complex 1 ( TSC1 , 5 cases), TSC2 (3 cases), and mammalian target of rapamycin (2 cases), with the majority classified as pathogenic or likely pathogenic. The CNS-HB cohort uniformly demonstrated somatic mutations in the von Hippel-Lindau gene. GPNMB was strong and diffuse in all 10 renal HBs and completely negative in CNS-HBs, reinforcing the molecular findings. Our study reveals a specific molecular hallmark in renal HB, characterized by recurrent TSC/mammalian target of rapamycin mutations, which defines it as a unique entity distinct from CNS-HB. This molecular finding potentially expands the therapeutic options for patients with renal HB. GPNMB can be considered for inclusion in immunohistochemical panels to improve renal HB identification.

Stereotactic Radiosurgery for Cranial and Spinal Hemangioblastomas: A Single-Institution Retrospective Series.

BACKGROUND AND OBJECTIVES: Stereotactic radiosurgery (SRS) has been an attractive treatment modality for both cranial and spinal hemangioblastomas, especially for multiple lesions commonly associated with von Hippel-Lindau (VHL) disease. This study aims to provide the largest long-term analysis of treatment efficacy and adverse effects of SRS for cranial and spinal hemangioblastomas at a single institution. METHODS: We evaluated the clinical and radiological outcomes of patients with hemangioblastomas treated with CyberKnife SRS at our institute from 1998 to 2022. The follow-up data were available for 135 hemangioblastomas in 35 patients. Twenty-eight patients had 123 hemangioblastomas associated with VHL, and 7 had 12 sporadic hemangioblastomas. The median age was 36 years, and the median tumor volume accounted for 0.4 cc. The SRS was administered with the median single-fraction equivalent dose of 18 Gy to the 77% median isodose line. RESULTS: At a median follow-up of 57 months (range: 3-260), only 20 (16.2%) of the VHL-associated and 1 (8.3%) sporadic hemangioblastomas progressed. The 5-year local tumor control rate was 91.3% for all hemangioblastomas, 91.7% among the sporadic lesions, and 92.9% in patients with VHL. SRS improved tumor-associated symptoms of 98 (74.8%) of 131 symptomatic hemangioblastomas, including headache, neck pain, dizziness, visual disturbances, dysesthesia, ataxia, motor impairment, seizures, and dysphagia. Two patients developed radiation necrosis (5.7%), and 1 of them required surgical resection. CONCLUSION: SRS is a safe and effective treatment option for patients with hemangioblastomas in critical locations, such as the brainstem, cervicomedullary junction, and spinal cord, and in patients with multiple hemangioblastomas associated with VHL disease.

The outcome of central nervous system hemangioblastomas in Von Hippel-Lindau (VHL) disease treated with belzutifan: a single-institution retrospective experience.

PURPOSE: Belzutifan is a Hypoxia Inducible Factor 2-alpha inhibitor approved in 2021 by the FDA for the treatment of renal cell carcinoma (RCC) in patients with Von-Hippel Landau (VHL) disease. These patients can also present with central nervous system (CNS) hemangioblastomas (HBs). We aim to study the effectiveness and adverse effects of belzutifan for CNS HBs, by reporting our preliminary institutional experience. METHODS: We present a series of VHL patients with CNS HBs undergoing treatment with belzutifan for RCC. All the included patients met the RECIST inclusion criteria. The clinical and radiological outcome measures included: Objective response rate (ORR), time-to-response (TTR), adverse events (AE), and patient response. Patient response was classified as partial response (PR), complete response (CR), progressive disease (PD), or stable disease (SD). RESULTS: Seven patients with 25 HBs were included in our study. A belzutifan dose of 120 mg/day PO was administered for a median of 13 months (range 10-17). Median follow up time was 15 months (range 10-24). An ORR of 71% was observed. The median TTR was 5 months (range: 1-10). None of the patients showed CR, while 5 patients (71.4%) showed PR and 2 (28.5%) showed SD. Among patients with SD the maximum tumor response was 20% [increase/decrease] of the lesion diameter. All the patients experienced decreased hemoglobin concentration, fatigue, and dizziness. None of the patients experienced severe anemia (grade 3-4 CTCAE). CONCLUSION: Belzutifan appears to be an effective and safe treatment for CNS hemangioblastoma in VHL patients. Further clinical trials to assess the long-term effectiveness of the medication are required.

Mutation in Chek2 triggers von Hippel-Lindau hemangioblastoma growth.

PURPOSE: Von Hippel-Lindau (VHL) is a rare inherited disease mainly characterized by the growth of tumours, predominantly hemangioblastomas (Hbs) in the CNS and retina, and renal carcinomas. The natural history of VHL disease is variable, differing in the age of onset and its penetrance, even among relatives. Unfortunately, sometimes VHL shows more severe than average: the onset starts in adolescence, and surgeries are required almost every year. In these cases, the factor that triggers the appearance and growth of Hbs usually remains unknown, although additional mutations are suspected. METHODS: We present the case of a VHL patient whose first surgery was at 13 years of age. Then, along his next 8 years, he has undergone 5 surgeries for resection of 10 CNS Hbs. To clarify this severe VHL condition, DNA from a CNS Hb and white blood cells (WBC) was sequenced using next-generation sequencing technology. RESULTS: Massive DNA sequencing of the WBC (germ line) revealed a pathogenic mutation in CHEK2 and the complete loss of a VHL allele (both tumour suppressors). Moreover, in the tumour sample, several mutations, in BRAF1 and PTPN11 were found. Familiar segregation studies showed that CHEK2 mutation was in the maternal lineage, while VHL was inherited by paternal lineage. CONCLUSIONS: Finally, clinical history correlated to the different genotypes in the family, concluding that the severity of these VHL manifestations are due to both, VHL-and-CHEK2 mutations. This case report aims to notice the importance of deeper genetic analyses, in inherited rare diseases, to uncover non-expected mutations.

18 F-PSMA-1007 PET/CT in a Case of Von Hippel-Lindau Syndrome.

ABSTRACT: We describe 18 F-PSMA-1007 PET/CT findings in case of von Hippel-Lindau syndrome with a cerebellar hemangioblastoma, 6 renal cell carcinomas in the bilateral kidneys, cystic lesions in the pancreas and left adrenal gland, and solid lesions in the bilateral epididymides. 18 F-PSMA-1007 PET/CT showed intense activity with SUV max of 111.3 of the cerebellar hemangioblastoma, variable activity with SUV max range of 6.4-37.6 of the renal cell carcinomas, and increased activity of the bilateral epididymal lesions (SUV max of 5.1 and 8.2 for the left and right epididymal lesions, respectively).

Hemangioblastomas and Other Vascular Origating Tumors of Brain or Spinal Cord.

Hemangioblastomas (HBs) are highly vascularized, slow-growing, rare benign tumors (WHO grade I). They account for about 2% of intracranial neoplasms; however, they are the most common primary cerebellar tumors in adults. Another frequent seat is the spinal cord (2-10% of primary spinal cord tumors). HBs are constituted by stromal and capillary vascular cells; macroscopically, HBs appear as nodular tumors, with or without cystic components. Although most of the HBs are sporadic (57-75%), they represent a particular component of von Hippel-Lindau disease (VHL), an autosomal dominant syndrome with high penetrance, due to a germline pathogenic mutation in the VHL gene, which is a tumor suppressor with chromosomal location on the short arm of chromosome three. VHL disease determines a variety of malignant and benign tumors, most frequently HBs, renal cell carcinomas, pheochromocytomas/paragangliomas, pancreatic neuroendocrine tumors, and endolymphatic sac tumors. Up to 20% of cases are due to de novo pathogenic variants without a family history. Many epidemiologic details of these tumors, especially the sporadic forms, are not well known. The median age of patients with sporadic HBS is about 40 years. More than two-third of VHL patients develop one or more central nervous system HBs during their lifetime; in case of VHL, patients at first diagnosis are usually younger than the patients with sporadic tumors. The most common presenting signs and symptoms are related to increased intracranial pressure, cerebellar signs, or spinal cord alterations in case of spinal involvement. Magnetic resonance imaging is the gold standard for the diagnosis, assessment, and follow-up of HBs, both sporadic and syndrome-related; angiography is rarely performed because the diagnosis is easily obtained with magnetic resonance. However, the diagnosis of an asymptomatic lesion does not automatically result in therapeutic actions, as the risks of treatment and the onset of possible neurological deficit need to be balanced, considering that HBs may remain asymptomatic and have a static or slow-growing behavior. In such cases, regular follow-up can represent a valid therapeutic option until the patients remain asymptomatic. There are no actual pharmacological therapies that are demonstrated to be effective for HBs. Surgery represents the primary therapeutic approach for these tumors. Observation or radiotherapy also plays a role in the long-term management of patients harboring HBs, especially in VHL; in few selected cases, endovascular treatment has been suggested before surgical removal. This chapter presents a systematic overview of epidemiology, clinical appearance, histopathological and neuroradiological characteristics of central nervous system HBs. Moreover, the genetic and molecular biology of sporadic and VHL HBS deserves special attention. Furthermore, we will describe all the available therapeutic options, along with the follow-up management. Finally, we will briefly report other vascular originating tumors as hemangioendotheliomas, hemangiomas, or angiosarcomas.

A bibliometric analysis of the top 100 cited articles for hemangioblastoma of the central nervous system.

Hemangioblastoma is a rare benign tumor that can affect the central nervous system sporadically or in association with von Hippel-Lindau (VHL) syndrome. Despite the advances in the medical field, hemangioblastoma still has a significant morbidity and mortality burden. This review gathered and analyzed this entity's top one hundred cited articles. The Scopus database was screened using the following keywords ("Hemangioblastoma" OR "Haemangioblastoma" OR "Hemangioblastomata"). The results were sorted by citation count, highest to lowest. Articles discussing hemangioblastoma of the central nervous system were included. Two independent reviewers extracted the article-, author-, and Journal-based data. Articles were classified into four categories: clinical features/ natural history, treatment, histopathology, review, or radiology. The location, brain, spine, or both, and type, sporadic, VHL-associated, or both, were used to classify the articles. The search query resulted in 4023 articles, and the top 100 most cited articles were included. The number of citations totaled 8781, averaging 87.81 CC per article. The included papers were published in 41 different journals between 1952 and 2014 by more than 11 departments from 65 institutions and 16 countries. The number of citations ranged from 46 to 333. The peak publication activity was before the 2000s, contributing to 62% of all articles, and the most prolific decade was 1990-2000, with 37 publications. We conducted a comprehensive bibliometric analysis of data from the most influential publications on central nervous system hemangioblastoma. We identified publication dynamics and research gaps. More high-impact studies are warranted to enhance disease comprehension and management.

Belzutifan in adults with VHL-associated central nervous system hemangioblastoma: a single-center experience.

PURPOSE: Belzutifan is a selective inhibitor of hypoxia-inducible factor 2 alpha (HIF-2a) that has emerged as a targeted therapy option for Von Hippel-Lindau (VHL) syndrome-associated tumors with recent FDA approval. There is limited real-world evidence regarding safety and efficacy in CNS hemangioblastoma. Our objective was to report on our clinical experience with belzutifan in adult patients with VHL-associated CNS hemangioblastoma. METHODS: We retrospectively reviewed our institutional experience of belzutifan in adult patients (> 18 years of age at time of therapy) with VHL and craniospinal CNS hemangioblastomas not amenable to surgical resection. The period for study review was October 2021 to March 2023. RESULTS: 4 patients (all female) with a median age of 36 years at time of belzutifan initiation were included. Median duration of therapy at last follow-up was 11 months (6-17 months). All patients had radiographic response to therapy after a median of 3 months (2-5 months), with maximal response to therapy after a median of 8 months (3-17 months). Therapy was well tolerated, with the most common adverse effect being anemia. No patients had treatment pauses or dose adjustments due to belzutifan-related toxicity. No patients experienced hypoxia. CONCLUSION: We showed that belzutifan is safe and well-tolerated with strong disease response for CNS hemangioblastoma in adults with VHL, supporting continued use of belzutifan in this patient population. Future studies should assess duration of treatment, effects of cessation after long-term use, and markers of therapeutic response.

[A Surgically Treated Depression]. / Eine chirurgisch behandelte Depression.

A Surgically Treated Depression Abstract. We present a 64-year-old patient with an unclear deterioration of her general condition due to a suspected depression. Despite antidepressive treatment, her condition further deteriorated. The CT/MRI of the skull showed a cerebellar tumor as well as a hydrocephalus obstructivus. Together with tumor staging, the histology, which revealed a hemangioblastoma, led to the diagnosis of VHL syndrome. Patients with VHL syndrome and their families should be included in a screening program, unless molecular genetic testing has ruled out the disease.

Supratentorial Hemangioblastoma in Adults: A Systematic Review and Comparison of Infratentorial and Spinal Cord Locations.

BACKGROUND: Supratentorial hemangioblastomas are benign and highly vascularized neoplasms that appear most often in the spine and posterior cranial fossa. They can also be located in the supratentorial compartment of the brain. We conducted a systematic review of the literature to better understand the clinical insights of supratentorial hemangioblastoma in adults. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the authors reviewed the English-language literature in the PubMed/MEDLINE database on supratentorial hemangioblastoma in adults, published in the past 40 years. We analyzed the differences between sporadic hemangioblastomas and hemangioblastomas associated with von Hippel-Lindau disease. In addition, we compared the characteristics of supratentorial hemangioblastomas with infratentorial and spinal cord locations. RESULTS: We reviewed 92 articles, describing 157 supratentorial hemangioblastomas in a total cohort of 148 adult patients. Most articles reporting supratentorial hemangioblastomas were published in the United States. Supratentorial hemangioblastomas occur more frequently in women than men. The median age at the time of diagnosis was 44.48 years. The sellar/parasellar region was the most commonly tumor location, while the most common morphological type was the solid type. Almost 80% of hemangioblastomas were completely resected; the outcome was favorable in more than 3 fourth of patients. CONCLUSIONS: Given their rarity, the literature on supratentorial hemangioblastomas is limited and based mostly on case reports. Complete surgical resection is the first choice of treatment and is associated with a good treatment outcome.

Stereotactic Radiosurgery for Spinal Haemangioblastoma: A Retrospective Single-Centre Experience from the United Kingdom.

INTRODUCTION: Haemangioblastoma is a benign, vascular tumour of the central nervous system. Stereotactic radiosurgery (SRS) is increasingly being used as a treatment for spinal lesions to avoid complex surgery, especially in patients with multi-focal tumours associated with von Hippel-Lindau syndrome (VHL). Here, we present the outcomes of patients treated in our centre using a CyberKnife VSI (Accuray, Inc.). METHODS: Retrospective analysis of all patients treated at our institution was conducted. Assessment of radiological response was based upon RANO criteria. Solid and overall tumour progression-free survival (PFS) was calculated using the Kaplan-Meier method. The development of a symptomatic new or enlarging cyst was included in the definition of progression when determining overall PFS. RESULTS: Fourteen tumours in 10 patients were included. Seven patients were male, and nine had VHL. Nine (64%) tumours had an associated cyst. The median (IQR) age at treatment was 45.5 (43.5-53) years. The median gross tumour volume was 0.355cc. Patients received a mean marginal prescribed dose of 9.6 Gy in a single fraction (median maximum dose: 14.3 Gy), which was constrained by spinal cord tolerance. Mean follow-up was 15.4 months. Radiologically, 11 (78.6%) tumours were stable or regressed and three (21.4%) progressed. Eight patients' symptoms improved or were stable, and two worsened, both of which were secondary to cyst enlargement. The 1-year solid-tumour and overall PFS was 92.3% and 75.7%, respectively. All patients were alive at the most recent follow-up. One patient developed grade 1 back pain following treatment. DISCUSSION/CONCLUSION: SRS appears to be a safe and effective treatment for spinal haemangioblastoma. Prospective trials with longer follow-up are required to establish the optimum management.

Investigation of germline VHL variants in Iranian patients with retinal capillary hemangioblastoma and genotype-phenotype analysis.

BACKGROUND: Retinal capillary hemangioblastoma (RCH), while sporadic in some cases, is the most common and earliest manifestation of von Hippel-Lindau disease (VHL). This is the first report on different types of VHL variants and genotype-phenotype correlations in Iranian families with RCH. MATERIALS AND METHODS: In this prospective observational case series study, 17 families with RCH were included. PCR was performed to amplify 3 exons of VHL gene. Afterward, Sanger sequencing was performed on all PCR products. For the detection of VHL copy number variations, MLPA was used. RESULTS: Our study identified 10 different types of VHL variants. Missense mutations were the most common variants found and affected the structure of α domain of the VHL protein (pVHL). The majority of mutations (72.7%) in the patients with RCH and central nervous system hemangioblastoma (CNS-HB) were located on α domain. CONCLUSION: α domain of VHL may play a potential role in the pathogenesis of RCH. Our findings suggest that genotype-phenotype characteristics in those variants in α- domain may predispose patients to RCH with CNS-HB.

How 'eye' helped in von Hippel-Lindau syndrome.

BACKGROUND: Von Hippel-Lindau syndrome is a rare autosomal dominantly inherited multisystemic oncologic syndrome, presenting predominantly with angiomatosis in embryologically similar neurologic tissue such as retina, cerebellum and adrenals. Retinal hemangioblastomas are the hallmark ophthalmic finding. In this case report, we describe the importance of timely diagnosis, thorough systemic examination and treatment of bilaterally asymmetrical retinal hemangioblastomas in a young adult male. CASE PRESENTATION: A 31-year-old male presented with painless diminution of vision in both eyes, associated with eyestrain and headache. Multiple asymmetric retinal lesions and dilated feeder vessels were noted on ophthalmoscopic examination and confirmed by fluorescein angiography to be retinal hemangioblastomas. Comprehensive systemic examination revealed cerebellar hemangioblastomas and multiple pancreatic and renal cysts. Treatment of retinal lesions was done by combination therapy of argon laser photocoagulation and cryopexy, which lead to a good visual outcome. Subsequently, neurosurgical resection of cerebellar hemangioblastoma proved to be lifesaving for the patient. CONCLUSION: RHBs are the earliest, easiest and the most frequently detected manifestation of VHL. Identification of ocular manifestations play a pivotal role in early diagnosis and timely intervention in VHL syndrome, thereby significantly reducing associated morbidity and mortality. Therefore, an ophthalmologist's role is crucial in the management of these potentially deadly tumours.

Extraneuraxial Hemangioblastoma: An Unusual Soft Tissue Neoplasm that Mimics More Common Entities but Carries Distinct Clinical Implications.

Hemangioblastoma, one of the characteristic tumors associated with Von Hippel-Lindau (VHL) disease, most often presents in the central nervous system (CNS) but can uncommonly arise in extraneuraxial, or previously referred to as peripheral, locations. Without the clinical context of known VHL disease, hemangioblastoma may not enter the differential for a soft tissue mass outside the CNS. Here, we present two patients with diagnostically challenging extraneuraxial hemangioblastoma to highlight the importance of considering this entity within the differential diagnosis of soft tissue neoplasms containing clear cells and delicate vasculature. We review the relevant diagnostic features, including a suggested immunohistochemical panel, along with the potential associated clinical implications of making this diagnosis. It is recommended that affected patients be offered genetic counseling to assess for underlying VHL disease.

Developmentally Arrested Basket/Stellate Cells in Postnatal Human Brain as Potential Tumor Cells of Origin for Cerebellar Hemangioblastoma in von Hippel-Lindau Patients.

von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary cancer disorder caused by a germline mutation in the VHL tumor suppressor gene. Loss of the wild-type allele results in VHL deficiency and the potential formation of cerebellar hemangioblastomas, which resemble embryonic hemangioblast proliferation and differentiation processes. Multiple, microscopic, VHL-deficient precursors, termed developmentally arrested structural elements (DASEs), consistently involve the cerebellar molecular layer in VHL patients, indicating the tumor site of origin. Unlike hemangioblastomas, however, cerebellar DASEs do not express brachyury, a mesodermal marker for hemangioblasts. In this study, neuronal progenitors occupying the molecular layer were investigated as tumor cells of origin. By immunohistochemistry, cerebellar DASEs and hemangioblastomas lacked immunoreactivity with antibody ZIC1 (Zic family member 1), a granule cell progenitor marker with concordance from oligonucleotide RNA expression array analyses. Rather, cerebellar DASEs and hemangioblastomas were immunoreactive with antibody PAX2 (paired box 2), a marker of basket/stellate cell progenitors. VHL cerebellar cortices also revealed PAX2-positive cells in Purkinje and molecular layers, resembling the histological and molecular development of basket/stellate cells in postnatal non-VHL mouse and human cerebella. These data suggest that VHL deficiency can result in the developmental arrest of basket/stellate cells in the human cerebellum and that these PAX2-positive, initiated cells await another insult or signal to form DASEs and eventually, tumors.

A meta-analysis of different von Hippel Lindau mutations: are they related to retinal capillary hemangioblastoma?

Retinal capillary hemangioblastomas (RCH) is a benign tumor that represents the initial manifestation in roughly half of Von Hippel Lindau (VHL) patients. They may also occur sporadically without systemic involvement. A first meta-analysis study was investigated to estimate the prevalence of Retinal capillary hemangioblastoma (RCH) in Von Hippel Lindau (VHL) syndrome, and its relation to type and location of mutations in VHL gene. The electronic databases of PubMed, Scopus, Embase, and Google Scholar were utilized to find eligible papers published up to May 2020. Lastly, after the different prevalence of RCH in Europe compared to other continents was noted, we decided to consider European and non-European patients separately. The Random effect model was used to evaluate the relation between developing RCH and types of mutations. The overall prevalence of RCH among VHL patients is about 47%. The prevalence of RCH was significantly higher in Europe in comparison with non-Europeans (p value < 0.001). Overall, the differences between the prevalence of RCH among different mutation types were not statistically significant. However, in Europe, the prevalence of RCH was significantly higher in patients with truncation mutation (p value = 0.007). In Europe, the RCH in VHL patients who had a mutation in exon 2 was significantly lower in comparison with exon 1 (p value = 0.001); but in non-Europeans, the prevalence of RCH in VHL patients that involved exon 2 was significantly higher in comparison with VHL patients with a mutation in exon1 (p value = 0.012). The highest risk of developing RCH was reported among Europeans. Overall, this study showed that the prevalence of RCH in VHL syndrome is not related to type or location of mutations and difference of RCH prevalence is probably depends on other genetic or environmental factor that should be considered in subsequent studies.

Endoscope-Assisted Resection for Cystic Cerebellar Hemangioblastomas.

BACKGROUND: Hemangioblastomas are benign, often cystic tumors occurring most commonly in the cerebellum. We describe resection of cystic cerebellar hemangioblastomas using an endoscope-assisted technique. METHODS: We present a series of 9 cases and discuss the endoscopic technique for resection of cystic hemangioblastoma. Frameless neuronavigation was used in all cases. A small 1- to 1.5-cm corticotomy lined with Surgicel and patties allows access to the peritumoral cyst. Using bimanual microsurgical techniques and the 30-degree rigid endoscope to provide visualization, the mural nodule can be resected and the cyst cavity inspected. RESULTS: Complete resection of the mural nodule was achieved in all cases. One patient had a postsurgery pseudomeningocele requiring ventriculoperitoneal shunt. Hospital length of stay was short for all the patients. CONCLUSIONS: Endoscope-assisted resection is a safe and effective technique for surgical resection of cystic hemangioblastoma.