von Hippel-Lindau disease: Updated guideline for diagnosis and surveillance

von Hippel Lindau disease (vHL) is caused by a hereditary predisposition to multiple neoplasms, especially hemangioblastomas in the retina and CNS, renal cell carcinomas (RCC), pheochromocytomas, neuroendocrine pancreatic tumours (PNET) and endolymphatic sac tumours. Evidence based approaches are needed to ensure an optimal clinical care, while minimizing the burden for the patients and their families. This guideline is based on evidence from the international vHL literature and extensive research of geno- and phenotypic characteristics, disease progression and surveillance effect in the national Danish vHL cohort. We included the views and preferences of the Danish vHL patients, ensured consensus among Danish experts and compared with international recommendations. RECOMMENDATIONS: vHL can be diagnosed on clinical criteria, only; however, in most cases the diagnosis can be supported by identification of a pathogenic or likely pathogenic variant in VHL. Surveillance should be initiated in childhood in persons with, or at risk of, vHL, and include regular examination of the retina, CNS, inner ear, kidneys, neuroendocrine glands, and pancreas. Treatment of vHL manifestations should be planned to optimize the chance of cure, without unnecessary sequelae. Most manifestations are currently treated by surgery. However, belzutifan, that targets HIF-2α was recently approved by the U.S. Food and Drug Administration (FDA) for adult patients with vHL-associated RCC, CNS hemangioblastomas, or PNETs, not requiring immediate surgery. Diagnostics, surveillance, and treatment of vHL can be undertaken successfully by experts collaborating in multidisciplinary teams. Systematic registration, collaboration with patient organisations, and research are fundamental for the continuous improvement of clinical care and optimization of outcome with minimal patient inconvenience.

Current Trends in the Surgical Management of Intramedullary Tumors: A Multicenter Study of 1,033 Patients by the Neurospinal Society of Japan

OBJECTIVE

We performed a retrospective observational study to demonstrate the surgical risks and long-term prognoses of intramedullary tumors in Japan using a multicenter registry authorized by the Neurospinal Society of Japan.

METHODS

Data from 1,033 consecutive patients with intramedullary tumors, treated between 2009 and 2020, were collected from 58 centers. Patients with spinal lipomas or myxopapillary ependymomas were excluded. Patient characteristics, clinical presentations, imaging characteristics, treatments, and outcomes were analyzed. The modified McCormick scale was used to classify functional status. Survival was described using Kaplan-Meier curves, and multivariable logistic regression analyses were performed.

RESULTS

The mean age of the patients was 48.4 years. Data of 361 ependymomas, 196 hemangioblastomas, 168 astrocytic tumors, 160 cavernous malformations, and the remaining 126 cases including subependymomas, metastases, schwannomas, capillary hemangiomas, and intravascular B-cell lymphomas were analyzed. Twenty-two patients were undiagnosed. The mean follow-up duration was 46.1 ± 38.5 months. Gross total tumor removal was achieved in 672 tumors (65.1%). On the modified McCormick scale, 234 patients (22.7%) had worse postoperative grades at the time of discharge. However, neurological status gradually improved. At 6 months postoperatively, 251 (27.5%), 500 (54.9%), and 160 patients (17.6%) had improved, unchanged, and worsened grades, respectively. Preoperative functional status, gross total tumor removal, and histopathological type were significantly associated with mortality and functional outcomes.

CONCLUSION

Our findings demonstrate better postoperative functional outcomes in patients with fewer preoperative neurological deficits. Degree of resection, postoperative treatments, and prognoses are closely related to the histology of intramedullary tumors.

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.

Solid vs. cystic predominance in posterior fossa hemangioblastomas: implications for cerebrovascular risks and patient outcome

BACKGROUND

Hemangioblastomas (HGBs) are highly vascular benign tumors, commonly located in the posterior fossa, and 80% of them are sporadic. Patients usually present with features of raised intracranial pressure and cerebellar symptoms. HGB can be classified as either mostly cystic or solids. Although the solid component is highly vascularized, aneurysm or hemorrhagic presentation is rarely described, having catastrophic results.

METHODS

We identified 32 consecutive patients with posterior fossa HBG who underwent surgery from 2008 through 2020 at our medical center. Tumors were classified as predominantly cystic or solid according to radiological features. Resection was defined as gross total (GTR) or subtotal (STR).

RESULTS

During the study period, 32 posterior fossa HGBs were resected. There were 26 cerebellar lesions and 4 medullar lesions, and in 2 patients, both structures were affected. Predominant cystic tumors were seen in 15 patients and solids in 17. Preoperative digital subtraction angiography (DSA) was performed in 8 patients with solid tumors, and 4 showed tumor-related aneurysms. Embolization of the tumors was performed in 6 patients, including the four tumor-related aneurysms. GTR was achieved in 29 tumors (91%), and subtotal resection in 3 (9%). Three patients had postoperative lower cranial nerve palsy. Functional status was stable in 5 patients (16%), improved in 24 (75%), and 3 patients (9%) deteriorated. One patient died 2 months after the surgery. Two tumors recurred and underwent a second surgery achieving GTR. The mean follow-up was 42.7 months (SD ± 51.0 months).

CONCLUSIONS

Predominant cystic HGB is usually easily treated as the surgery is straightforward. Those with a solid predominance present a more complex challenge sharing features similar to arteriovenous malformations. Given the important vascular association of solid predominance HGB with these added risk factors, the preoperative assessment should include DSA, as in arteriovenous malformations, and endovascular intervention should be considered before surgery.

Imaging manifestations of von Hippel-Lindau disease: an illustrated guide focusing on the central nervous system

Von Hippel-Lindau (VHL) disease is a rare, autosomal dominant inherited syndrome that affects the germline of the VHL gene, a tumor suppressor gene. VHL disease is characterized by the multisystemic development of a variety of benign and malignant tumors, especially in the central nervous system (CNS). Such tumors include retinal and CNS hemangioblastomas, as well as endolymphatic sac tumors. The various tumor sites are responsible for the diversity of signs and symptoms related to the disease. The mean age at symptom onset is 33 years. Despite medical advances, the average life expectancy of patients with VHL disease is 49 years. Imaging plays a pivotal role in the clinical diagnosis and is essential to the follow-up of patients with VHL disease. This pictorial essay describes characteristic CNS manifestations of VHL disease-related tumors that all radiology residents should be aware of.

Tool-Tissue Forces in Hemangioblastoma Surgery

OBJECTIVE

Surgical resection of intracranial hemangioblastoma poses technical challenges that may be difficult to impart to trainees. Here, we introduce knowledge of tool-tissue forces in Newton (N), observed during hemangioblastoma surgery.

METHODS

Seven surgeons (2 groups: trainees and mentor), with mentor (n = 1) and trainees (n = 6, PGY 1-6 including clinical fellowship), participated in 6 intracranial hemangioblastoma surgeries. Using sensorized bipolar forceps, we evaluated tool-tissue force profiles of 5 predetermined surgical tasks: 1) dissection, 2) coagulation, 3) retracting, 4) pulling, and 5) manipulating. Force profile for each trial included force duration, average, maximum, minimum, range, standard deviation (SD), and correlation coefficient. Force errors including unsuccessful trial bleeding or incomplete were compared between surgeons and with successful trials.

RESULTS

Force data from 718 trials were collected. The mean (standard deviation) of force used in all surgical tasks and across all surgical levels was 0.20 ± 0.17 N. The forces exerted by trainee surgeons were significantly lower than those of the mentor (0.15 vs. 0.24; P < 0.0001). A total of 18 (4.5%) trials were unsuccessful, 4 of them being unsuccessful trial-bleeding and the rest, unsuccessful trial-incomplete. The force in unsuccessful trial-bleeding was higher than successful trials (0.3 [0.09] vs. 0.17 [0.11]; P = 0.0401). Toward the end of surgery, higher force was observed (0.17 vs. 0.20; P < 0.0001).

CONCLUSIONS

The quantification of tool-tissue forces during hemangioblastoma surgery with feedback to the surgeon, could well enhance surgical training and allow avoidance of bleeding associated with high force error.

Tractional retinal detachment and juxtapapillary retinal capillary hemangioma in a 6-year-old girl: A case report

A 6-year-old girl with visual impairment in the right eye (OD) was referred for an eye evaluation. The fundus of the OD showed a fibrotic orange endophytic lesion located adjacent to the optic disc. In retinal optical coherence tomography, a local tractional retinal detachment and choroidal neovascular membrane were observed together also with the presence of subretinal fluid. Due to the vision of the OD evolved to nonlight perception in the following exam, enucleation was performed. The pathology report was correlated with hemangioblastoma. Herein, we describe a case of a young girl with a retinal hemangioblastoma with quick evolution and without prior systemic diagnosis.

Adrenal hemangioblastoma

Hemangioblastoma (HB) is a rare benign tumor that most commonly occurs in the cerebellum. HB is composed of neoplastic stromal cells and abundant small vessels. However, the exact origin of stromal cells is controversial. Extraneural HBs have been reported in a small series, and peripheral HBs arising in the adrenal gland are extremely rare. Herein, we report a case of sporadic adrenal HB in a 54-year-old woman. The tumor was a well-circumscribed, yellow mass measuring 4.2 cm in diameter. Histologically, the tumor was composed of small blood vessels and vacuolated stromal cells with clear cytoplasm. On immunohistochemical stain, the stromal cells were positive for S-100 protein, neuron-specific enolase, and synaptophysin. The tumor did not reveal mutation of VHL alleles. We herein present a case of HB of the adrenal gland and review of the literature.

β-Catenin marks proliferating endothelial cells in glioblastoma

BACKGROUND

Angiogenesis is a key process in the growth and maintenance of tumors. The Wnt signaling pathway is required for angiogenesis of the central nervous system though development of the blood-brain barrier and subsequent proliferation of endothelial cells during tumor growth. However, the specificity of the Wnt pathway in regulating endothelial cells of different central nervous systems remains to be investigated.

MATERIALS & METHODS

Patient-derived tissue samples from 35 paraffin-embedded tumors were used to assess β-catenin immunoexpression. Tumor samples consisted of the following pathologies: grade II diffuse astrocytoma, glioblastoma, hemangioblastoma, and metastatic adenocarcinoma (lung or breast primary). Average percent reactivity was recorded as a mean observed in ten high-power fields. The following scale was used to grade immunoreactivity: 0 = immunonegative, 1 = 1-25% reactive, 2 = 26-50% reactive, 3 = 51-75% reactive, 4 = 76-100% reactive.

RESULTS

While we did not observe nuclear expression of β-catenin in any samples, there was uniform cytoplasmic expression of β-catenin within glial tumor cells. There was a clear distinction in tumor endothelial cells whereby diffuse staining was noted in areas of microvascular hyperplasia in GBM and a less immunoreactive profile in low-grade astrocytomas. By contrast, non-glial tumors, contained very minimal cytoplasmic β-catenin expression in tumor and stromal cells and were devoid of immunoreactivity in endothelial cells.

CONCLUSION

β-catenin is unique marker of proliferating endothelial cells in GBM. Therapies targeting the spatial and structural heterogeneity inherent to GBM may prove to be efficacious and result in an improved survivorship.

Spinal hemangioblastomas: analysis of surgical outcome and prognostic factors

The prognostic factors for surgically removed spinal hemangioblastomas, the impact of VHL disease on outcome, and the role of intraoperative neuromonitoring are still not completely clear. The aim of this study was to review our experience with spinal hemangioblastomas in order to assess potential predictors of neurological outcome after surgery. All cases of spinal hemangioblastomas removed at two Italian academic institutions from 1985 to 2020 were reviewed. Data about clinical presentation and symptom duration, diagnosis of VHL, surgical approach, use of IONM, duration of hospital stay, follow-up, and modified McCormick grade before and after surgery were extracted. Sixty-one patients (31 F, 30 M) underwent 69 surgeries to remove 74 spinal hemangioblastomas (37 cervical, 32 thoracic, 5 lumbar). Improvement was found in 32.3% of cases, neurological condition remained stable in 51.6% of cases, and deteriorated in 16.1% of patients. A worsening trend in VHL patients and an improvement trend in non-VHL patients were detected, despite the lack of statistical significance. Laminotomy and use of IONM were found to be associated with better outcome, although no association was found between surgery without IONM and worse outcome. In most cases, patients affected by spinal hemangioblastomas can expect a good long-term outcome. In our experience, laminotomy seems to be associated with better outcome compared to laminectomy. While its absence is not associated with worse outcome, IONM seems to be associated with a better neurological outcome. Our study suggests that the more impaired the preoperative neurological condition, the worse the outcome.

Treatment Strategy for Giant Solid Hemangioblastomas in the Posterior Fossa: A Retrospective Review of 13 Consecutive Cases

OBJECTIVE

To analyze radiologic characteristics, treatment strategy, and treatment outcomes of posterior fossa giant solid hemangioblastomas (GSHBs; ≥4 cm in maximum diameter).

METHODS

We performed a retrospective study of 13 consecutive patients (9 male and 4 female patients; mean age, 57.5 ± 13.3 years; range, 24-76 years) with GSHB who underwent surgical resection at a single institution between 2002 and 2018. The median follow-up was 33 months (range, 12-120 months). For each patient, neuroimaging findings, operative record, and treatment outcome were reviewed.

RESULTS

Seven tumors (53.8%) were located within cerebellar hemispheres, 4 (30.8%) in proximity to the brainstem, 1 (7.7%) within the cerebellar vermis, and 1 (7.7%) in the cerebellopontine angle. The mean maximum diameter was 4.8 ± 0.8 cm (range, 4.0-6.7 cm). Gross total resection was achieved in 11 patients (84.6%), and near-total resection in 2 patients (15.4%). Surgical complications occurred in 5 patients (38.5%); persistent neurologic deficits occurred in 2 patients (15.4%). Estimated progression-free survival after surgery was 92.3%, 80.8%, and 80.8% at 1, 5, and 10 years, respectively, whereas the estimated 1-year, 5-year, and 10-year overall survival was 100%, 90%, and 90%, respectively.

CONCLUSIONS

GSHBs are surgically challenging. The current study shows that favorable outcome can be achieved for GSHBs in the cerebellar hemispheres and vermis. For those involving the brainstem, planned near-total resection or subtotal resection in a piecemeal fashion can be attempted if en bloc resection is judged to be infeasible, and further intervention can be considered as needed.

Novel Clinical Insights into Spinal Hemangioblastoma in Adults: A Systematic Review

BACKGROUND

Hemangioblastomas (HBs) are well-vascularized, benign central nervous system tumors and the third most common primary spinal cord tumor after astrocytoma/ependymoma, occurring sporadically or as a part of autosomal dominant von Hippel-Lindau disease, in which tumors are often multiple and prone to relapse. Spinal HBs are commonly located in the cervical cord and associated with a syrinx formation. Owing to location and growth trends, they may cause significant neurological deficit, impairing quality of life. We conducted a systematic review to understand better clinical insights into spinal HB in adults and compare spinal HB versus posterior cranial fossa HB.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for conducting systematic reviews, we reviewed the English-language literature on adult spinal HB in the MEDLINE/PubMed database over the last 40 years.

RESULTS

We reviewed 237 articles on adult spinal HB and analyzed national and continental distribution, clinical symptoms, tumor location and presence of syringomyelia, treatment strategies and postoperative complications, histology and immunochemistry, and treatment outcomes. We compared individual characteristics in sporadic and von Hippel-Lindau disease spinal HBs. Finally, we compared features of posterior cranial fossa and spinal HBs.

CONCLUSIONS

Spinal cord HBs most commonly have a dorsal intramedullary location. Total surgical tumor resection is the first treatment option; preoperative embolization may be performed to reduce intraoperative bleeding and surgical time. HBs located in the spine have decreased mortality and rate of infection, but increased rates of cardiopulmonary complications compared with HBs in the posterior cranial fossa.

Pathogenicity of VHL variants in families with non-syndromic von Hippel-Lindau phenotypes: An integrated evaluation of germline and somatic genomic results

Von Hippel-Lindau (VHL) syndrome is a hereditary tumor syndrome associated with germline loss-of-function pathogenic variants (PVs) in the VHL gene. VHL is classically associated with a high penetrance for many different tumor types. The same tumors may be sporadic in the setting of somatic VHL PVs. With more large-scale genome sequencing, variants with low penetrance or variable expressivity are identified. This has introduced challenges in patient management and the clinical interpretation of germline VHL variants identified in non-classic families. Herein, we report individuals from 3 non-classic families with VHL variants who presented with unexpected or non-syndromic phenotypes, but often with a VHL component tumor. In family 1, two siblings, age 61, with pathogenic VHL p.Leu188Val presented with clear cell renal cell carcinoma and lobular breast cancer. In family 2, the proband, age 82, was found to have pathogenic germline VHL p.Tyr98His on testing for metastatic bladder cancer. In family 3, four members carried germline VHL p.Pro81Ser (variant of uncertain significance), after the proband, age 40, presented with cerebellar hemangioblastoma. None of the individuals in the above three families met clinical criteria of classic VHL, suggesting germline VHL p.Leu188Val, p.Y98H, and p.Tyr98His may be low penetrant variants. Large studies are needed to evaluate penetrance and possible effect of genetic and non-genetic modifiers. Somatic sequencing performed on their respective tumors could help discern the etiology of the component tumors, highlighting the role of somatic evaluation in these cases. Paired examination of somatic and germline findings provided a more complete landscape of genome alterations in cancer development.

Parasagittal cystic meningioma mimicking hemangioblastoma: A case report

Background:

Cystic meningioma is a rare variety with similar histological profiles like the solid tumors. It has been documented in both supratentorial and infratentorial compartments presenting radiologically as a large cyst with mural nodule mimicking hemangioblastoma.

Case Description:

We managed a middle-aged woman who presented with recurrent seizures and brain MRI revealed left frontal cystic parasagittal tumor with mural nodule. She had left frontal awake craniotomy and gross total tumor excision. Histology confirmed meningothelial meningioma.

Conclusion:

Cystic meningioma is rare but should be high in differentials of cystic intracranial tumor with dural based nodules. Awake craniotomy is possible for the excision of parasagittal tumor most especially when it is frontal in location.

Cerebellar hemangioblastoma: Case report with review of the literature

Originally recognized by Cushing and Bailey, hemangioblastoma is a developmental vascular neoplasm that is predominantly found in the posterior fossa. It is a highly vascularized tumor, with well-differentiated histologic features. Although rare, it remains the most common primary tumor of cerebellum in adults, along with metastases. MRI is the gold standard, allowing a precise characterization of the lesion's features, and its relationship with the surrounding structures. We report the case of a patient with a cerebellar symptomatology, in whom brain MRI raises the diagnosis of hemangioblastoma, which was then confirmed by histopathologic examination.

Hemangioblastoma of the Peripheral Nervous System: A Critical Analysis of Its Rarity in Von Hippel-Lindau Disease

Von Hippel-Lindau (VHL) disease is a multisystem disease cause by germline mutations of the VHL tumor suppressor gene. Hemangioblastomas are the most common manifestation of VHL disease and can occur in the central nervous system in up to 90% of these patients. By contrast, we found only one true case of a peripheral nervous system (PNS) hemangioblastoma in the setting of VHL. We explore the possible reasons behind the lack of PNS hemangioblastomas in VHL disease.

Resection of a Medulla Oblongata Hemangioblastoma: 2-Dimensional Operative Video

Hemangioblastomas are benign vascular tumors that can be sporadic or multiple, as part of Von Hippel-Lindau disease. They develop at any level of the central nervous system, with a predilection for the dorsal medulla among brainstem locations. Radical resection of the solid portion of the tumor is the best treatment option.1,2 The resection should be en bloc to avoid uncontrollable intraoperative hemorrhage hindering safe dissection. Preservation of the venous drainage during the progressive dissection of the tumor of the surrounding structures and interruption of numerous small arterial feeders is a tenet for safe surgical resection.3 Once the tumor is completely disconnected, the large draining veins can be coagulated, and the tumor removed. We demonstrate these technical principles in the surgery of a 30-yr-old female with an exophytic hemangioblastoma from the dorsal medulla obstructing the fourth ventricle outflow. We demonstrate the resection of this lesion through a suboccipital craniotomy in a sitting position.4 The patient consented to the surgery and publication of images. Image at 1:26 from Kadri and Al-Mefty,4 by permission from the Congress of Neurological Surgeons.

Sporadic hemangioblastoma of the kidney: a clinicopathologic study of three cases and a literature review

Much attention has been paid to renal hemangioblastoma, but there are still challenges in its differential diagnosis. Three cases (2 men, 1 woman; age: 40–56 years) presented with renal tumors. The tumors were surrounded by a thick fibrous capsule, well-demarcated from the surrounding renal parenchyma, and composed of sheets or nests of polygonal to short spindle-shaped tumor cells with a rich capillary network. In cases 1 and 3, the large polygonal tumor cells contained abundant pale or eosinophilic cytoplasm, and some possessed intracytoplasmic lipid vacuoles. In case 2, tumor cells were characterized by a uniform size, mild, clear, or lightly stained cytoplasm, and typical "clear cell" appearance. Immunohistochemistry revealed that the polygonal stromal cells were strongly and diffusely positive for α-inhibin, neuron-specific enolase (NSE), S100 protein, and vimentin. Cluster of differentiation (CD)10 and paired box gene (PAX)8 were positive, while epithelial membrane antigen (EMA) and cytokeratin (CK) were focally positive in case 3. CD34 and CD31 outlined the contours and distribution of the vascular networks. Renal hemangioblastoma is rare and prone to misdiagnosis; more attention should be paid to the morphological features and reasonable application of immunohistochemistry in the diagnosis of hemangioblastoma.

Pineal Region Hemangioblastoma Resection Through Paramedian Supracerebellar Approach: 2-Dimensional Operative Video

Pineal region tumors remain challenging lesions to safely resect because of their central location.1 Patients frequently present with symptoms associated with hydrocephalus and brainstem compression.2 Local anatomy, primarily the tentorium angle and venous anatomy, plays a central role in the selection of the approach.3 The paramedian supracerebellar approach pioneered by Yaşargil in 19844 allows to access the pineal region through a less steep angle while avoiding the central thickened arachnoid and midline cerebellar and vermian veins.3 Although the author strongly prefers the advantageous three-quarter concord position, this early case was performed in a sitting position, which requires a bubble test to rule out the presence of a persistent foramen ovale. The preoperative pineal differential diagnosis should be exhaustive, including blood and cerebrospinal fluid (CSF) tumor markers in suitable cases. Hemangioblastomas are seldom found or expected in the pineal area, and the surgeon must be alarmed by their typical "cherry nodule" appearance.2,5 Their recognition prior to resection is paramount in avoiding excessive blood loss from tumor entry. Similar to arteriovenous malformations, hemangioblastoma surgical tenets include en bloc resection and preservation of the main draining veins until the last steps of the resection. Von Hippel-Lindau (VHL) syndrome genetic workup is necessary is similar patients, as more than 25% of hemangioblastomas are associated with VHL tumor suppressor gene mutations in chromosome 3.2 The patient consented to the surgery and use of her photography. Image at 2:41 from Ueyama et al, Bridging veins on the tentorial surface of the cerebellum: a microsurgical anatomic study and operative considerations, Neurosurgery, 1998, 43(5),3 used with permission from the Congress of Neurological Surgeons.

Surgical management of sporadic hemangioblastomas located in the posterior fossa of brain

PURPOSE

Hemangioblastomas (HBs) are highly vascular tumors, constituting 2%-3% of central nervous system (CNS) tumors. Surgery is a treatment option for HBs. The purpose of this study was to evaluate the demographic, clinical, and radiological findings of patients with HBs who were operated on via microsurgical technique at our clinic and to determine the findings specific to HBs and evaluate their pathological findings and confirmation.

METHODS

We evaluated age, gender, initial complaints and duration of 100 patients (50 female and 50 male patients), presence of cranial nerve deficits, magnetic resonance imaging, data (localization, presence of hydrocephalus, tumor size, enhancement pattern, and cystic and solid component features), resection rates, pathological findings (grade, Ki-67 ratio, and staining results), recurrence, special conditions of patients, and the final status of patients in this study.

RESULTS

Mean age was 39.08 ± 14.77 years and 66.7% of the patients presented with cerebellar findings. Five of the cases were located in the brainstem, five were located in the cerebellopontine angle, and two were in the cerebellar cortex. In all patients, gross total resection was performed using arteriovenous malformation repair.

CONCLUSIONS

Surgical intervention of small and cystic tumors can be performed safely with en bloc resection along with preoperative detailed imaging, improved microsurgical techniques, and an extensive understanding of anatomical and vascular structures. On the contrary, patients with a brainstem invasion and solid structure present surgical difficulties due to arteriovenous malformation-like vascularizations; therefore, gross total resection is the optimal treatment in HBs.

Microsurgical Resection of an Intramedullary Spinal Cord Hemangioblastoma Through an Anterior Cervical Approach: 2-Dimensional Operative Video

This video demonstrates the microsurgical removal of an intramedullary spinal cord hemangioblastoma through an anterior cervical approach. While most spinal hemangioblastomas arise from the dorsal or dorsolateral pial surface and can be safely resected through a posterior approach,1,2 ventral tumors can present a significant challenge to safe surgical removal.3-5 This patient presented with a progressively symptomatic ventral pial based hemangioblastoma at the C5-6 level with large polar cysts extending from C3 to T1. The tumor was approached through a standard anterior cervical exposure with a C5 and C6 corpectomy. Following midline durotomy, the tumor was identified and complete microsurgical resection was achieved. The principles and techniques of tumor resection are illustrated and described in the video. Following tumor resection and dural closure, a fibular allograft was inserted into the corpectomy defect and a C4-C7 fixation plate was placed. The patient was maintained in a supine position for 36 h. He was discharged home on postoperative day 3 in a cervical collar. The patient did well with near-complete recovery of neurological function. Postoperative magnetic resonance imaging at 6 wk showed a substantial resolution of the polar cysts and no evidence of residual tumor. The patient featured in this video consented to the procedure.

Second-Window Indocyanine Green for Visualization of Hemangioblastoma: A Case Report With Two-Dimensional Operative Video

BACKGROUND AND IMPORTANCE

The proper differentiation of neoplastic tissue from adjacent brain parenchyma can pose a great challenge, especially in eloquent areas of the brain. With the novel technique, "Second-Window Indocyanine Green," injection of a near-infrared fluorophore (ICG) allows for intraoperative visualization of tumors by taking advantage of the compromised vasculature surrounding the tumor. Thus, such a technique may demonstrate utility for hemangioblastomas, which are hypervascular tumors of the central nervous system.

CLINICAL PRESENTATION

Here we present the case of a 39-yr-old male with a demonstrated cystic mass in the left cerebellum, with additional edema spreading towards the vermis. A total of 5 mg/kg of ICG was delivered intravenously 24 h prior to the operation. The tumor was approached via the infratentorial suboccipital approach. We observed strong near-infrared fluorescence through the intact dura, consistent with the tumor location. Surgical pathology confirmed a final diagnosis of cerebellar hemangioblastoma. There was complete resection of the tumor, with the patient discharged uneventfully.

CONCLUSION

We report the first successful case of fluorescence-guided surgery of a cerebellar hemangioblastoma using near-infrared fluorescence imaging with the Second-Window ICG technique. This joins a growing series of publications that demonstrate the efficacy of a novel application of ICG, a near-infrared fluorophore, in accurate intraoperative visualization of neoplastic tissue. While the use of a dedicated near-infrared platform (ie, the VisionSense Iridium [Visionsense, Philadelphia, Pennsylvania]) yields a higher signal-to-background ratio, a neurosurgical microscope (ie, the Leica OH6 [Leica Microsystems, Wetzlar, Germany]) may also provide a suitable option in cases where fluorescence is very strong.

Spontaneous Subarachnoid Haemorrhage in Spinal Hemangioblastoma: Illustrative Case and Discussion of a Pathophysiological Hypothesis

Spontaneous non-aneurysmal subarachnoid haemorrhage (naSAH) is an unusual finding that could be burdened by significant mortality and morbidity rates. Rare pathologies and delayed diagnosis could be advocated as responsible of unfavourable outcomes. Herein, we describe an exceedingly rare giant lumbar spinal hemangioblastoma (80 × 23 mm) presenting as an intracranial naSAH. Based on our radiological and clinical findings a pathophysiological hypothesis linking intracranial naSAH to venous hypertension was discussed for the first time even among lumbar spinal tumors. Although rare, unusual causes should be investigated in presence of radiological atypical finding as a prompt evaluation and treatment could be needed.

Retinal Hemangioblastoma with Extraocular Extension: Report of Three Cases

Retinal hemangioblastoma (RH) is the earliest and most common clinical manifestation in Von Hippel-Lindau (VHL) disease. RH can also present in isolation without any evidence of VHL. Clinical course of RH can be stationary or progress to exudation and chronic retinal detachment requiring surgical intervention. We report 3 cases of aggressive RH with extraocular extension in young males causing painful blind eye requiring enucleation. Two of our cases were bilateral involvement and had systemic manifestations of VHL. The third patient had unilateral involvement with no systemic evidence of VHL. This manifestation of RH is rarely reported. Two of our patients with VHL had early manifestations of RH and had undergone multiple cryotherapy sessions as well as retinal detachment surgery for exudative retinal detachment. This differential should be considered in vascular lesion arising from intraocular structures especially in diagnosed patients of VHL. The cases also highlight the aggressive behaviour and long-term progression of RH in some patients despite early treatment.