Edema is a precursor to central nervous system peritumoral cyst formation

Supratentorial hemangioblastoma: correlation between phenotype, gender and vascular territory affected

Supratentorial hemangioblastomas are rare, vascular lesions. The presence of peri-tumoral cysts and edema has meaningful clinical, diagnostic and therapeutic implications. Nevertheless, the pathogenesis of both cyst and edema formation is not fully understood. This study sought to determine if the radiologic phenotype of supratentorial hemangioblastoma is affected by the different cerebral arterial circulations. Review of the English-language literature from 1973 to 2023 yielded 53 cases of parenchymal supratentorial hemangioblastomas eligible for analysis. Patients were divided by the vascular territorial distribution of the lesions: anterior circulation (n = 36) or posterior circulation (n = 17), and the groups were compared for demographic, clinical, radiologic and molecular variables. Univariate analyses yielded a significant difference between the groups in five variables. Cystic changes and "classic" radiological phenotype were associated with hemangioblastomas of the posterior circulation (OR = 0.19, p = 0.045 and OR = 0.287, p = 0.048, respectively), while female gender, significant peritumoral edema and purely solid phenotype were associated with hemangioblastomas of the anterior circulation (OR = 3.384, p = 0.045 and OR = 5.25, p = 0.05 and OR = 14.0, p = 0.015; respectively). On multivariate analysis, solid phenotype and female gender remained significantly associated with the anterior circulation (OR = 36.04, p = 0.014 and OR = 4.45, p = 0.045). The incidence of von-Hippel Lindau disease was higher in the anterior-circulation group. Cystic tumors were present in all females in the posterior-circulation group compared to 43.4% in the anterior-circulation group (OR = 20.714, 95% CI 1.061 to 404.122; p = 0.045). Based on historical cases of supratentorial hemangioblastoma, this study shows that different tumor phenotypes are associated with the different cerebral circulations. Gender was also associated with differences in tumor distribution and radiologic phenotype. These novel data may improve our understanding of unique vascular diseases of the central nervous system.

Proteomic Analysis on Sequential Samples of Cystic Fluid Obtained from Human Brain Tumors

Cystic formation in human primary brain tumors is a relatively rare event whose incidence varies widely according to the histotype of the tumor. Composition of the cystic fluid has mostly been characterized in samples collected at the time of tumor resection and no indications of the evolution of cystic content are available. We characterized the evolution of the proteome of cystic fluid using a bottom-up proteomic approach on sequential samples obtained from secretory meningioma (SM), cystic schwannoma (CS) and cystic high-grade glioma (CG). We identified 1008 different proteins; 74 of these proteins were found at least once in the cystic fluid of all tumors. The most abundant proteins common to all tumors studied derived from plasma, with the exception of prostaglandin D2 synthase, which is a marker of cerebrospinal fluid origin. Overall, the protein composition of cystic fluid obtained at different times from the same tumor remained stable. After the identification of differentially expressed proteins (DEPs) and the protein-protein interaction network analysis, we identified the presence of tumor-specific pathways that may help to characterize tumor-host interactions. Our results suggest that plasma proteins leaking from local blood-brain barrier disruption are important contributors to cyst fluid formation, but cerebrospinal fluid (CSF) and the tumor itself also contribute to the cystic fluid proteome and, in some cases, as with immunoglobulin G, shows tumor-specific variations that cannot be simply explained by differences in vessel permeability or blood contamination.

Sclerosing meningioma with a large peritumoral cyst: Case report

Meningioma morphology is diverse. Although unlisted in the WHO classification, sclerosing meningioma is a rare variation featuring an extremely low signal intensity on MRI T2-weighted imaging. About 50 cases of sclerosing meningiomas, including spinal tumors, have been reported; however, cases with an accompanying large peritumoral cyst remain unreported. Here, we first report a rare case of sclerosing meningioma with a large peritumoral cyst and review relevant literature.

α-SMA positive vascular mural cells suppress cyst formation in hemangioblastoma

Approximately 60% of hemangioblastomas (HBs) have peritumoral cysts adjacent to the tumor, which can cause neurological deficits due to the mass effect, and the management of cyst formation is a clinical challenge. Vascular mural cells surrounding endothelial cells consist of vascular smooth muscle cells (vSMCs) and pericytes, which are essential elements that support blood vessels and regulate permeability. This study investigated the involvement of mural cells in cyst formation. We analyzed the expression of α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor-beta (PDGFRB), and CD31 in 39 consecutive human cerebellar HBs, 20 of cystic and 19 of solid type. Solid type HBs showed stronger diffuse expression of α-SMA in precapillary arterioles and capillaries within the tumor than cystic type HBs (p = 0.001), whereas there was no difference in PDGFRB and CD31 expression. Detailed observation with immunofluorescence demonstrated that α-SMA was expressed in vascular mural cells surrounding capillaries in the solid rather than in the cystic type. Multivariate analysis including various clinical and pathological factors showed that lower α-SMA expression was significantly correlated with cyst formation (p < 0.001). Our data suggested that vascular mural cells from precapillary arterioles to capillaries expressing α-SMA may be pericytes and play a crucial role in HB cystogenesis.

Presentation, imaging, patterns of care, growth, and outcome in sporadic and von Hippel-Lindau-associated central nervous system hemangioblastomas

OBJECT

Hemangioblastoma is a relatively rare neoplasm occurring mostly in the cerebellum that may arise sporadically or in the context of von Hippel-Lindau (VHL) syndrome. Presentation, imaging, natural history, surgical patterns of care, and outcomes are incompletely defined for this uncommon lesion. We reviewed our large institutional series to help clarify these issues.

METHODS

Retrospective analysis of consecutive, neurosurgically managed CNS hemangioblastomas at Mayo Clinic, 1988-2018.

RESULTS

Two hundred and eighty five hemangioblastomas were treated in 184 unique patients (115 sporadic, 69 VHL). Compared to sporadic patients, VHL patients were younger (36.7 vs 51.7 years; p < 0.0001), were treated while asymptomatic more commonly (47.3 vs 4.2%; p < 0.0001), had smaller lesions (6.6 vs 13.9 mL; p < 0.0001), and harbored lesions with associated cysts less frequently (51.0 vs 75.0%; p = 0.0002). Macrocystic tumor architecture was associated with larger lesion size and greater symptom severity. Solid lesions later formed cysts at a median 130 months. Growth in both total volume and solid component accelerated after cyst formation (10.6 and 6.0 times median rate prior to cyst emergence). VHL patients died at a younger age (47.9 vs 74.5, p = 0.0017) and were more likely to die of direct disease sequelae. Though treatment-free survival time was significantly longer in sporadic cases, a substantial fraction (> 40%) developed tumor recurrence/progression requiring additional treatment.

CONCLUSIONS

Hemangioblastoma presentation varies with etiology and clinical course is more complicated in VHL cases. Nodular lesions often develop cysts over time which is associated with accelerated tumor growth. Sporadic cases have a previously unappreciated but substantial risk of late recurrence/progression requiring treatment.

Multiple VHL-related hemangioblastomas and holocord syrinx: identifying the causative lesion. Illustrative case

BACKGROUND

Brainstem and spinal cord hemangioblastomas are a common manifestation of von Hippel–Lindau (VHL) disease. Cysts and associated syringes are the most common cause of significant morbidity in these patients. Surgical treatment of symptomatic hemangioblastomas are often complicated by the presence of multiple potential lesions, leading to cyst and syrinx formation.

OBSERVATIONS

The authors present a case of a patient with multiple VHL-related hemangioblastomas who presented with syringobulbia and holocord syrinx. Resection of two cyst wall hemangioblastomas and one cervical hemangioblastoma only transiently improved syringobulbia. Eventual resolution of syringobulbia and collapse of the holocord syrinx only occurred following removal of a large lower thoracic hemangioblastoma.

LESSONS

Surgical management of hemangioblastomas and associated cysts in patients with VHL should only target lesions most likely contributing to neurological deficits as excess surgical intervention risks treatment-related morbidity. The authors illustrate how anatomical and pathophysiological considerations as well as patient symptoms are key to identifying target lesions for resection and developing deliberate treatment plans.

Handcrafted and Deep Learning-Based Radiomic Models Can Distinguish GBM from Brain Metastasis

Objective

The purpose of this study was to investigate the feasibility of applying handcrafted radiomics (HCR) and deep learning-based radiomics (DLR) for the accurate preoperative classification of glioblastoma (GBM) and solitary brain metastasis (BM).

Methods

A retrospective analysis of the magnetic resonance imaging (MRI) data of 140 patients (110 in the training dataset and 30 in the test dataset) with GBM and 128 patients (98 in the training dataset and 30 in the test dataset) with BM confirmed by surgical pathology was performed. The regions of interest (ROIs) on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and contrast-enhanced T1WI (T1CE) were drawn manually, and then, HCR and DLR analyses were performed. On this basis, different machine learning algorithms were implemented and compared to find the optimal modeling method. The final classifiers were identified and validated for different MRI modalities using HCR features and HCR + DLR features. By analyzing the receiver operating characteristic (ROC) curve, the area under the curve (AUC), accuracy, sensitivity, and specificity were calculated to evaluate the predictive efficacy of different methods.

Results

In multiclassifier modeling, random forest modeling showed the best distinguishing performance among all MRI modalities. HCR models already showed good results for distinguishing between the two types of brain tumors in the test dataset (T1WI, AUC = 0.86; T2WI, AUC = 0.76; T1CE, AUC = 0.93). By adding DLR features, all AUCs showed significant improvement (T1WI, AUC = 0.87; T2WI, AUC = 0.80; T1CE, AUC = 0.97; p < 0.05). The T1CE-based radiomic model showed the best classification performance (AUC = 0.99 in the training dataset and AUC = 0.97 in the test dataset), surpassing the other MRI modalities (p < 0.05). The multimodality radiomic model also showed robust performance (AUC = 1 in the training dataset and AUC = 0.84 in the test dataset).

Conclusion

Machine learning models using MRI radiomic features can help distinguish GBM from BM effectively, especially the combination of HCR and DLR features.

Central Nervous System Hemangioblastoma in a Pediatric Patient Associated With Von Hippel-Lindau Disease: A Case Report and Literature Review

Background

Hemangioblastoma is a benign tumor of the central nervous system and may appear as a component of von Hippel-Lindau (VHL) disease. At present, approximately 40 cases of optic nerve HGBs have been reported in the literature. VHL disease is a rare autosomal-dominant inherited cancer syndrome with different phenotypes caused by variants in the VHL gene. Herein, the authors describe a case of a pediatric patient with VHL disease and with optic nerve HGB, a rare phenotypic expression. The purpose of this study was to explore the genotype-phenotype, clinical features, treatment and follow-up of VHL-associated hemangioblastomas in pediatric patients.

Case Description

A 12-year-old boy presented with vision loss, headache and dizziness at our hospital. Magnetic resonance imaging (MRI) revealed a large (19.8 mm*18.5 mm*23.5 mm) irregular mass located in the suprasellar region. The mass was successfully removed after craniotomy and microsurgical treatment. The pathological diagnosis was left optic nerve HGB. Genetic analyses showed p.Pro86Leu (c. 257C>T) heterozygous missense mutations in the VHL gene.

Conclusion

This is the first reported pediatric case of VHL-associated optic nerve HGB. The genotype-phenotype correlation of VHL disease may provide new evidences for predicting tumor penetrance and survival. Gross tumor resection combined with stereotactic radiosurgery might be the most beneficial treatment.

Hemangioblastoma with Contrast-Enhanced Cystic Wall: When the Surgical Rule Must Not Be Respected

OBJECTIVE

The purpose of this paper is to describe the variation of surgical plan and technique required in a rare subset of hemangioblastomas compared with the accepted general strategy. The established rule in hemangioblastoma surgery is to avoid cyst wall removal, as it is not neoplastic, and it will not recur if mural nodule is completely removed. However, the wall of the associated cyst is occasionally enhanced by gadolinium on preoperative magnetic resonance imaging.

METHODS

We present the case of a patient with a hemangioblastoma that was progressively compressed by a growing cyst, with the final appearance of a contrast-enhanced cyst wall. We collected similar cases reported in the literature.

RESULTS

Our study points out the need for a tailored preoperative strategy, the usefulness of intraoperative fluorescent dyes, and the crucial role of frozen section histopathologic analysis to confirm diagnosis and optimize treatment.

CONCLUSIONS

When a hemangioblastoma is associated with a contrast-enhanced cyst, care must be taken to intraoperatively confirm the presence of neoplastic cells and eventually remove the neoplastic cyst wall to reduce the risk of recurrence.

Combined transcriptomic and lipidomic analysis reveals aberrant lipid metabolism in central nervous system hemangioblastomas

Peritumoral cysts are commonly detected in the central nervous system tumors, especially hemangioblastomas (HBs). However, the molecular mechanisms driving their formation and propagation are still unknown. We conducted an integrated lipidomics and transcriptomics analysis on solid and cystic HB samples in order to elucidate the changes in the lipid profile and expression of lipid metabolism-related genes during cyst formation. Transcriptomic analysis revealed differential expression of several genes between the solid and cystic HBs, and those associated with lipid metabolism, such as ADCY4, MGLL, ACOT2, DGKG, SHC1 and LPAR2, were markedly dysregulated in the cystic HBs. The lipidomic analysis further showed a significant reduction in the abundance of triacylglycerol, ceramide, lysophosphatidylcholine and lysophosphatidylethanolamine, and an increase in phosphatidylcholine and phosphatidylethanolamine levels in the cystic HBs. Furthermore, bioinformatics analysis revealed altered lipid biosynthesis, glycerophospholipid metabolism and phospholipase activity in the cystic HBs. Taken together, our findings indicate that cyst formation in HBs is related with aberrant lipid metabolism.

Immunohistochemical Profiles of Matrix Metalloproteinases and Vascular Endothelial Growth Factor Overexpression in the Antoni B Area of Vestibular Schwannomas

OBJECTIVE

To evaluate the clinical manifestations of cystic vestibular schwannomas (VSs), investigate the immunohistochemical profiles of matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) expression in Antoni A and B areas, and speculate the pathogenesis of cystic formation and intratumoral hemorrhage.

METHODS

Clinical features and outcomes of 24 cases of cystic VSs and 38 cases of solid VSs were retrospectively compared. Immunohistochemical studies were conducted to evaluate the characteristics of MMPs and VEGF in cystic and solid VSs.

RESULTS

The tumor size was 38.92 ± 1.86 mm and 31.95 ± 1.74 mm in the cystic and solid VSs group, respectively (P = 0.011). Cystic VSs were rich in the Antoni B area. MMP-9 expression was low in the Antoni A and B areas. MMP-2 was moderately expressed. No significant difference in MMP-2 expression existed between the Antoni A and B areas (P > 0.05). VEGF and MMP-14 expression were moderate in the Antoni A area and intense in the Antoni B area, and the expression of both was significantly greater in the Antoni B area than in the Antoni A area (P < 0.001).

CONCLUSIONS

MMP-14 and VEGF expression were significantly greater in the Antoni B area than in the Antoni A area. Upregulated MMP-14 may degrade loose collagen in the Antoni B area and contribute to cystic formation. MMP-14 can enhance VEGF activity, which may induce extravasation of a plasma ultrafiltrate, cystic expansion, and intratumoral hemorrhage. Therefore, MMP-14 inhibition may be a therapeutic strategy for treating cystic VSs.

Von Hippel-Lindau Disease: Current Challenges and Future Prospects

Understanding of molecular mechanisms of tumor growth has an increasing impact on the development of diagnostics and targeted therapy of human neoplasia. In this review, we summarize the current knowledge on molecular mechanisms and their clinical implications in von Hippel-Lindau (VHL) disease. This autosomal dominant tumor syndrome usually manifests in young adulthood and predisposes affected patients to the development of benign and malignant tumors of different organ systems mainly including the nervous system and internal organs. A consequent screening and timely preventive treatment of lesions are crucial for patients affected by VHL disease. Surgical indications and treatment have been evaluated and optimized over many years. In the last decade, pharmacological therapies have been evolving, but are largely still at an experimental stage. Effective pharmacological therapy as well as detection of biomarkers is based on the understanding of the molecular basis of disease. The molecular basis of von Hippel-Lindau disease is the loss of function of the VHL protein and subsequent accumulation of hypoxia-inducible factor with downstream effects on cellular metabolism and differentiation. Organs affected by VHL disease may develop frank tumors. More characteristically, however, they reveal multiple separate microscopic foci of neoplastic cell proliferation. The exact mechanisms of tumorigenesis in VHL disease are, however, still not entirely understood and knowledge on biomarkers and targeted therapy is scarce.

Subependymoma of the Conus Medullaris with Cystic Formation: Case Report and a Literature Review

BACKGROUND

Subependymoma in the spinal cord is very rare and usually occurs in the cervical cord. We report an exceptional case of subependymoma that occurred at the conus medullaris with cystic formation. This article reviews the literature on subependymoma in the conus medullaris; discusses its clinical manifestations, imaging findings, and differential diagnoses; and offers an opinion about the cystic formation of the subependymoma.

CASE DESCRIPTION

A 69-year-old woman experienced progressive limb weakness with a somatosensory abnormality for 3 months. Preoperative magnetic resonance imaging showed a cystic intramedullary lesion at the conus medullaris with a well-defined margin. A preliminary diagnosis of epidermoid cyst was made based on the imaging findings. During the operation, cystic formation of the tumor was found, and the tumor was completely removed. Pathology showed an uneven proliferation of glial cells, consistent with subependymal morphology, and the tumor was confirmed as subependymoma.

CONCLUSIONS

We present an extremely rare case of cystic formation in subependymoma at the conus medullaris. Subependymoma should be included in the differential diagnosis of intramedullary cystic lesions. The breakdown of the blood-brain barrier and excessive extravasation may be potential mechanisms of cystic formation.

Machine Learning Decision Tree Models for Differentiation of Posterior Fossa Tumors Using Diffusion Histogram Analysis and Structural MRI Findings

We applied machine learning algorithms for differentiation of posterior fossa tumors using apparent diffusion coefficient (ADC) histogram analysis and structural MRI findings. A total of 256 patients with intra-axial posterior fossa tumors were identified, of whom 248 were included in machine learning analysis, with at least 6 representative subjects per each tumor pathology. The ADC histograms of solid components of tumors, structural MRI findings, and patients' age were applied to construct decision models using Classification and Regression Tree analysis. We also compared different machine learning classification algorithms (i.e., naïve Bayes, random forest, neural networks, support vector machine with linear and polynomial kernel) for dichotomized differentiation of the 5 most common tumors in our cohort: metastasis (n = 65), hemangioblastoma (n = 44), pilocytic astrocytoma (n = 43), ependymoma (n = 27), and medulloblastoma (n = 26). The decision tree model could differentiate seven tumor histopathologies with terminal nodes yielding up to 90% accurate classification rates. In receiver operating characteristics (ROC) analysis, the decision tree model achieved greater area under the curve (AUC) for differentiation of pilocytic astrocytoma (p = 0.020); and atypical teratoid/rhabdoid tumor ATRT (p = 0.001) from other types of neoplasms compared to the official clinical report. However, neuroradiologists' interpretations had greater accuracy in differentiating metastases (p = 0.001). Among different machine learning algorithms, random forest models yielded the highest accuracy in dichotomized classification of the 5 most common tumor types; and in multiclass differentiation of all tumor types random forest yielded an averaged AUC of 0.961 in training datasets, and 0.873 in validation samples. Our study demonstrates the potential application of machine learning algorithms and decision trees for accurate differentiation of brain tumors based on pretreatment MRI. Using easy to apply and understandable imaging metrics, the proposed decision tree model can help radiologists with differentiation of posterior fossa tumors, especially in tumors with similar qualitative imaging characteristics. In particular, our decision tree model provided more accurate differentiation of pilocytic astrocytomas from ATRT than by neuroradiologists in clinical reads.

Hemangioblastoma and von Hippel-Lindau disease: genetic background, spectrum of disease, and neurosurgical treatment

INTRODUCTION

Hemangioblastomas are rare, histologically benign, highly vascularized tumors of the brain, the spinal cord, and the retina, occurring sporadically or associated with the autosomal dominant inherited von Hippel-Lindau (VHL) disease. Children or adults with VHL disease have one of > 300 known germline mutations of the VHL gene located on chromosome 3. They are prone to develop hemangioblastomas, extremely rarely starting at age 6, rarely at age 12-18, and, typically and almost all, as adults. There is a plethora of VHL-associated tumors and cysts, mainly in the kidney, pancreas, adrenals, reproductive organs, and central nervous system. Due to a lack of causal treatment, alleviation of symptoms and prevention of permanent neurological deficits as well as malignant transformation are the main task. Paucity of data and the nonlinear course of tumor progression make management of pediatric VHL patients with hemangioblastomas challenging.

METHODS

The Freiburg surveillance protocol was developed by combining data from the literature and our experience of examinations of > 300 VHL patients per year at our university VHL center.

RESULTS

Key recommendations are to start screening of patients at risk by funduscopy with dilated pupils for retinal tumors with admission to school and with MRI of the brain and spinal cord at age 14, then continue biannually until age 18, with emergency MRI in case of neurological symptoms. Indication for surgery remains personalized and should be approved by an experienced VHL board, but we regard neurological symptoms, rapid tumor growth, or critically large tumor/cyst sizes as the key indications to remove hemangioblastomas. Since repeated surgery on hemangioblastomas in VHL patients is not rare, modern neurosurgical techniques should encompass microsurgery, neuronavigation, intraoperative neuromonitoring, fluorescein dye-based intraoperative angiography, intraoperative ultrasound, and minimally invasive approaches, preceded in selected cases by endovascular embolization. Highly specialized neurosurgeons are able to achieve a very low risk of permanent morbidity for the removal of hemangioblastomas from the cerebellum and spinal cord. Small retinal tumors of the peripheral retina can be treated by laser coagulation, larger tumors by cryocoagulation or brachytherapy.

CONCLUSION

We consider management at experienced VHL centers mandatory and careful surveillance and monitoring of asymptomatic lesions are required to prevent unnecessary operations and minimize morbidity.

Origin of Syrinx Fluid in Syringomyelia: A Physiological Study

BACKGROUND

The origin of syrinx fluid is controversial.

OBJECTIVE

To elucidate the mechanisms of syringomyelia associated with cerebrospinal fluid pathway obstruction and with intramedullary tumors, contrast transport from the spinal subarachnoid space (SAS) to syrinx was evaluated in syringomyelia patients.

METHODS

We prospectively studied patients with syringomyelia: 22 with Chiari I malformation and 16 with SAS obstruction-related syringomyelia before and 1 wk after surgery, and 9 with tumor-related syringomyelia before surgery only. Computed tomography-myelography quantified dye transport into the syrinx before and 0.5, 2, 4, 6, 8, 10, and 22 h after contrast injection by measuring contrast density in Hounsfield units (HU).

RESULTS

Before surgery, more contrast passed into the syrinx in Chiari I malformation-related syringomyelia and spinal obstruction-related syringomyelia than in tumor-related syringomyelia, as measured by (1) maximum syrinx HU, (2) area under the syrinx concentration-time curve (HU AUC), (3) ratio of syrinx HU to subarachnoid cerebrospinal fluid (CSF; SAS) HU, and (4) AUC syrinx/AUC SAS. More contrast (AUC) accumulated in the syrinx and subarachnoid space before than after surgery.

CONCLUSION

Transparenchymal bulk flow of CSF from the subarachnoid space to syrinx occurs in Chiari I malformation-related syringomyelia and spinal obstruction-related syringomyelia. Before surgery, more subarachnoid contrast entered syringes associated with CSF pathway obstruction than with tumor, consistent with syrinx fluid originating from the subarachnoid space in Chiari I malformation and spinal obstruction-related syringomyelia and not from the subarachnoid space in tumor-related syringomyelia. Decompressive surgery opened subarachnoid CSF pathways and reduced contrast entry into syringes associated with CSF pathway obstruction.

Histologic findings associated with laser interstitial thermotherapy for glioblastoma multiforme

Background

Laser-interstitial thermal therapy (LITT) has been supported by some authors as an ablative treatment of glioblastoma multiforme (GBM). Although the effects of LITT have been modeled in vivo, the histologic effects in a clinical circumstance have not been described. We analyzed tissue from a patient who underwent LITT as primary treatment for GBM.

Case presentation

A 62-year-old male was diagnosed with a left temporal GBM and underwent LITT at an outside institution. Despite corticosteroid therapy, the patient was referred with increasing headache and acalculia associated with progressive peritumoral edema two weeks after LITT procedure. En bloc resection of the enhancing lesion and adjacent temporal lobe was performed with steroid-independent symptom resolution (follow-up, > 2 years). Histologic analysis revealed three distinct histologic zones concentrically radiating from the center of the treatment site. An acellular central region of necrosis (Zone 1) was surrounded by a rim of granulation tissue with macrophages (CD68) (Zone 2; mean thickness, 1.3 ± 0.3 mm [±S.D.]). Viable tumor cells (identified by Ki-67, p53 and Olig2 immunohistochemistry) were found (Zone 3) immediately adjacent to granulation tissue. The histologic volume of thermal tissue ablation/granulation was consistent with preoperative (pre-resection) magnetic resonance (MR)-imaging.

Conclusion

These findings are the first in vivo in humans to reveal that LITT causes a defined pattern of tissue necrosis, concentric destruction of tumor and tissue with viable tumor cells just beyond the zones of central necrosis and granulation. Furthermore, MR-imaging appears to be an accurate surrogate of tissue/tumor ablation in the early period (2 weeks) post-LITT treatment. Surgery is an effective strategy for patients with post-LITT swelling which does not respond to steroids.

A case report on cystic meningioma in cerebellopontine angle and recommendations for management

RATIONALE

Cystic meningioma located at the cerebellopontine angle (CPA) is an extremely rare occurrence. It is frequently misdiagnosed preoperatively. Little is known about the clinical features and outcome of this rare disease.

PATIENT CONCERNS

A 70-year-old male presenting with progressive headache and gait disturbance.

DIAGNOSIS

According to the symptoms, signs, and Gd-enhanced magnetic resonance images (MRI), a preoperative diagnosis of hemangioblastoma located in left CPA was made. Finally, the histological examination revealed a meningioma.

INTERVENTIONS

A complete resection, including the part of the solid mass together with cyst, was performed.

OUTCOMES

The postoperative course of the patient was uneventful, and no residual or recurrent tumor was found during the 24-month follow-up period.

LESSONS

Cystic meningioma should be included in the differential diagnosis of a CPA mass with atypical radiologic features, such as a large cyst and enhanced mural nodule. By summarizing the related literature, we found that the most common pathological subtype of CPA cystic meningioma is the clear cell subtype, which belongs to WHO grade II. Gross total resection including the enhanced cyst wall is extremely important. A close follow-up is necessary because of the high recurrence rate in this subset of meningioma.

Pediatric central nervous system hemangioblastomas: different from adult forms? A retrospective series of 25 cases

BACKGROUND

Pediatric hemangioblastomas are rare, and the clinical features, timing of surgical intervention, optimal treatment, and clinical outcomes are still unclear.

METHODS

We performed a retrospective study of all patients with CNS hemangioblastomas who were treated at West China Hospital from January 2003 to March 2015. Patients under the age of 16 years were included in the study. The medical records of these patients were reviewed and statistically analyzed.

RESULTS

Twenty-five children (15 females and ten males, [mean age 12.6 ± 4.7 years, range 1-16 years]) presented with hemangioblastomas. Tumors were detected in the cerebellum, brainstem, and spinal cord in 40, 28, and 32% of patients, respectively. Sixteen children (64%) had VHL syndrome. The most frequent symptoms were those related to increased intracranial pressure. The mean duration of symptoms was 1.5 ± 2.1 months. Preoperative hydrocephalus was noted in 11 children (44%). Gross total resection was achieved in all children. Clinical symptoms improved in 19 children (76%), unchanged in four children (16%), and aggravated in two children (8%), respectively. The mean follow-up was 44.5 ± 32.3 months. Five patients (20%) experienced disease progression. Using univariate analysis, both tumor-associated cysts (P = 0.027) and VHL disease (P = 0.032) were significantly related to postoperative outcomes.

CONCLUSIONS

Pediatric hemangioblastomas have many different clinical features compared with adult cases. A high degree of suspicion for VHL disease should be raised in pediatric hemangioblastomas. Despite many challenges involved, surgical outcomes for pediatric hemangioblastomas are favorable. Lifelong follow-up is mandatory to detect the disease progression.

Surgical treatment of cerebellar hemangioblastomas

BACKGROUND

Hemangioblastomas (HBL) are uncommon tumors of the central nervous system (CNS), corresponding to 1-2.5% of all intracranial tumors. They can present sporadically or in patients with von Hippel-Lindau (VHL) disease and are most often located in the cerebellum, brainstem, and spinal cord. VHL disease is a multiple neoplasia syndrome inherited in an autosomal dominant fashion and caused by a VHL suppressor gene deletion. We present our experience in the management of patients with cerebellar HBL.

METHODS

Thirty consecutive patients with cerebellar HBL were included in this study. Hospital charts, radiological images, and operative records were reviewed. Modified Rankin scores were used to evaluate the clinical course.

RESULTS

Thirty patients diagnosed with cerebellar HBL were operated. Complete total resection was achieved in 93% of the cases. Postoperatively, 83% of the patients showed good functional recovery.

CONCLUSIONS

HBL of the cerebellum should be resected when symptomatic or when the tumor (or a tumor-associated cyst) shows signs of enlargement. Surgical intent should seek en bloc resection to minimize intraoperative bleeding. Patients with HBLs must be tested for VHL gene mutations, and in confirmed cases, relatives should be offered genetic counseling.

Vascular hyperpermeability as a hallmark of phacomatoses: is the etiology angiogenesis comparable with mechanisms seen in inflammatory pathways? Part I: historical observations and clinical perspectives on the etiology of increased CSF protein levels, CSF clotting, and communicating hydrocephalus: a comprehensive review

Phacomatoses are a special group of familial hamartomatous syndromes with unique neuro-cutaneous manifestations as well as disease characteristic tumors. Neurofibromatosis 2 (NF2) and tuberous sclerosis complex (TSC) are representatives of this family. Vestibular schwannoma (VS) and subependymal giant cell tumor (SGCT) are two of the most common intracranial tumors associated with NF2 and TSC, respectively. These tumors can present with obstructive hydrocephalus due to their location adjacent to or in the ventricles. However, both tumors are also known to have a unique association with an elevated protein concentration in the cerebrospinal fluid (CSF), sometimes in association with non-obstructive (communicating) hydrocephalus (HCP), the causality of which has been unclear. Furthermore, SGCTs have repeatedly been shown to have a predisposition for CSF clotting, causing debilitating obstructions and recurrent malfunctions in shunted patients. However, the exact relation between high protein levels and spontaneous clotting of the CSF is not clear, nor is the mechanism understood by which CSF may clot in SGCTs. Elevated protein levels in the CSF are thought to be caused by increased vascular permeability and dysregulation of the blood-brain barrier. The two presumed underlying pathophysiologic mechanisms for that, in the context of tumorigenesis, are angiogenesis and inflammation. Both mechanisms are correlated to the Pi3K/Akt/mTOR pathway which is a major tumorigenesis pathway in nearly all phacomatoses. In this review, we discuss the influence of angiogenesis and inflammation on vascular permeability in VSs and SGCTs at the phenotypic level as well as their possible genetic and molecular determinants. Part I describes the historical perspectives and clinical aspects of the relationship between vascular permeability, abnormal CSF protein levels, clotting of the CSF, and communicating HCP. Part II describes different cellular and molecular pathways involved in angiogenesis and inflammation in these two tumors and the correlation between inflammation and coagulation. Interestingly, while increased angiogenesis can be observed in both VS and SGCT, inflammatory processes seem more prominent in SGCT. Both pathologies are characterized by different subgroups of tumor-associated macrophages (TAM): the pro-inflammatory, M1 type is predominating in SGCTs while pro-angiogenetic, M2 type is predominating in VSs. We suggest that lack of NF2 protein in VS and lack of TSC1/2 proteins in SGCT determine this fundamental difference between the two tumor types, by defining the predominant TAM type. Since inflammatory reactions and coagulation processes are tightly connected, a "pro-inflammatory state" of SGCT can be used to explain the observed associated enhanced CSF clotting process. These distinct cellular and molecular differences may have direct therapeutic implications on tumors that are unique to certain phacomatoses or those with similar genetics.

Expression of angiopoietins in central nervous system hemangioblastomas is associated with cyst formation

PURPOSE

This study aimed to determine the expression of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), and endothelial tyrosine kinase receptor (Tie-2) in central nervous system (CNS) hemangioblastomas (HBs) and explore the correlation with peritumoral cyst formation.

METHOD

A total of 22 paraffin-embedded specimens derived from 11 cyst-associated and 11 solid solitary CNS HBs were collected for streptavidin-peroxidase immunohistochemical staining. The expression levels of Ang-1, Ang-2 and Tie-2 in cystic and solid HBs were estimated and compared according to the integrated optical density (IOD) of staining in the sections. To further confirm the differential expression of Ang-1 and Ang-2 between cystic and solid HBs, an additional 9 frozen specimens from 5 cyst-associated and 4 solid solitary HBs were collected for Western blot analysis. Clinical histories and radiological records of the patients were reviewed retrospectively.

RESULTS

Compared to normal cerebellum tissue, Ang-1, Ang-2 and Tie-2 were prominently overexpressed in both the stromal cells and endothelial cells of CNS HBs. The expression of Ang-2 and the ratio of Ang-2/Ang-1 in the cystic group were significantly higher than those in the solid group. The intensity of Ang-2 expression in the cystic group was negatively correlated with age. There was no correlation between the expression level of the proteins and sex, tumor location, tumor volume or cyst volume.

CONCLUSIONS

Ang/Tie signaling is upregulated in HBs and is likely associated with the process of intense vascularization and cyst formation. Higher Ang-2 levels and a higher Ang-2/Ang-1 ratio may contribute to cyst formation by increasing the vascular permeability. The decrease in Ang-2 expression with advanced age in cystic-associated HBs may be associated with the reduced growth rate of peritumoral cysts among elderly patients. Ang-2 shows great potential as an effective therapeutic target of symptomatic CNS HBs associated with cysts.

Personalized Medicine for Nervous System Manifestations of von Hippel-Lindau Disease

von Hippel–Lindau disease (VHL) is a familial neoplasia syndrome associated with multisystem tumor development. Depending on tumor type and location, current treatments for VHL-associated tumors can include a combination of chemotherapy, radiation therapy, and/or surgery. Central nervous system (CNS) manifestations of VHL include craniospinal hemangioblastomas and endolymphatic sac tumors (ELSTs). While the first-line treatment for both types of VHL-associated CNS tumors is surgery, the indications for treatment are patient specific and different for each tumor type. Although early sign/symptom formation is the primary indication for resection of craniospinal hemangioblastomas, radiographic discovery (asymptomatic and symptomatic) of ELSTs can be an indication for resection of ELSTs in VHL patients. Recently, research has revealed that specific VHL germline mutations may permit targeted medical treatments of not only CNS manifestations of VHL-associated tumors but also visceral tumors. Specifically, missense mutations can result in the translation of functional VHL protein (pVHL) that is rapidly degraded resulting in functional loss of the pVHL, and inhibitors of pVHL degradation may slow protein degradation and restore pVHL function. Emerging research will investigate the safety and practicality of using potential targeted therapies.

Activation of hypoxia signaling induces phenotypic transformation of glioma cells: implications for bevacizumab antiangiogenic therapy

Glioblastoma (GBM) is the most common and deadly primary brain tumor in adults. Bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), can attenuate tumor-associated edema and improve patient symptoms but based on magnetic resonance imaging, is associated with non-enhancing tumor progression and possibly gliosarcoma differentiation. To gain insight into these findings, we investigated the role of hypoxia and epithelial-mesenchymal transition (EMT)-associated proteins in GBM. Tumor markers of hypoxia and EMT were upregulated in bevacizumab-treated tumors from GBM patients compared to untreated counterparts. Exposure of glioma cells to 1% oxygen tension increased cell proliferation, expression of EMT-associated proteins and enhanced cell migration in vitro. These phenotypic changes were significantly attenuated by pharmacologic knockdown of hypoxia-inducible Factor 1α (HIF1α) or HIF2α, indicating that HIFs represent a therapeutic target for mesenchymal GBM cells. These findings provide insights into potential development of novel therapeutic targeting of angiogenesis-specific pathways in GBM.

Supratentorial haemangioblastoma without von Hippel-Lindau syndrome in an adult: A rare tumor with review of literature

Supratentorial hemangioblastomas (HBLs) are rare, benign vascular tumors of the central nervous system neoplasms. Very scarce literature is available regarding supratentorial HBL without von Hippel–Lindau (VHL) syndrome in an adult. We reviewed the literature and PubMed advanced search showed only a few results of supratentorial HBL without VHL syndrome. We reported a rare case of cystic supratentorial HBL in 39-year-old male affecting the parietal lobe without VHL syndrome. Supratentorial HBL is a rare tumor and supratentorial HBL without VHL syndrome are even rarer. Being a rare entity, not much clinical data is currently available regarding supratentorial HBLs, thus necessitating the need for further reporting and review of such cases.

Biological and clinical impact of hemangioblastoma-associated peritumoral cysts in von Hippel-Lindau disease

OBJECTIVE

Peritumoral cysts are frequently associated with CNS hemangioblastomas and often underlie neurological morbidity and mortality. To determine their natural history and clinical impact, the authors prospectively analyzed hemangioblastoma-associated peritumoral cysts in patients with von Hippel-Lindau (VHL) disease.

METHODS

Patients with VHL disease who had 2 or more years of follow-up and who were enrolled in a prospective study at the National Institutes of Health were included. Serial prospectively acquired laboratory, genetic, imaging, and clinical data were analyzed.

RESULTS

One hundred thirty-two patients (of 225 in the VHL study with at least 2 years of follow-up) had peritumoral cysts that were followed for more than 2 years (total of 292 CNS peritumoral cysts). The mean age at study entrance was 37.4 ± 13.1 years ([mean ± SD], median 37.9, range 12.3-65.1 years). The mean follow-up was 7.0 ± 1.7 years (median 7.3, range 2.1-9.0 years). Over the study period, 121 of the 292 peritumoral cysts (41.4%) became symptomatic. Development of new cysts was associated with a larger number cysts at study enrollment (p = 0.002) and younger age (p < 0.0001). Cyst growth rate was associated with anatomical location (cerebellum cysts grew faster than spine and brainstem cysts; p = 0.0002 and p = 0.0008), younger age (< 35 years of age; p = 0.0006), and development of new neurological symptoms (p < 0.0001). Cyst size at symptom production depended on anatomical location (p < 0.0001; largest to smallest were found, successively, in the cerebellum, spinal cord, and brainstem). The most common location for peritumoral cysts was the cerebellum (184 cysts [63%]; p < 0.0001).

CONCLUSIONS

Peritumoral cysts frequently underlie symptom formation that requires surgical intervention in patients with VHL disease. Development of new cysts was associated with a larger number of cysts at study enrollment and younger age. Total peritumoral cyst burden was associated with germline partial deletion of the VHL gene.

Peritumoral cysts associated with pituitary macroadenoma

OBJECT

Peritumoral cysts are benign nonneoplastic cysts that are found adjacent to extraaxial brain tumors such as meningiomas, schwannomas, craniopharyngiomas, and esthesioneuroblastomas. Peritumoral cysts associated with pituitary macroadenomas have not been previously described in the literature. The authors report 6 cases of giant macroadenoma-associated peritumoral cysts and delineate their imaging spectrum.

METHODS

The authors retrospectively reviewed the records of 179 patients diagnosed with pituitary macroadenomas who underwent tumor resection at their institution and had preoperative MRI scans available for review. The patients were evaluated for the presence of associated peritumoral cysts. Clinical presentation, histopathology, follow-up time, tumor and peritumoral cyst dimensions were recorded. Signal intensity on T1-weighted, T2-weighted, diffusion-weighted, and FLAIR sequences, as well as pre- and postcontrast appearance, were determined.

RESULTS

Six patients (3.4%) with associated peritumoral cysts were identified in our cohort of 179 patients with pituitary macroadenoma. Twelve patients in the cohort had giant macroadenomas (≥ 4.0 cm), and 50% of these tumors had associated peritumoral cysts with significant extrasellar extension of the macroadenoma. Only tumors with craniocaudal, transverse, and anteroposterior diameters of 3.6 × 3.4 × 4.2 cm to 7.0 × 7.4 × 6.8 cm (mean 5.3 × 5.1 × 5.6 cm), respectively, had associated peritumoral cysts. The growth pattern in all tumors was suprasellar, with predominant anterior and lateral extension. Cysts showed T1-weighted, T2-weighted, and FLAIR hyperintensity in 67%, 67%, and 60% of patients, respectively. There was no contrast enhancement of the cyst wall or fluid contents in any patient. Postoperatively, cysts had completely resolved (4 of 5) or significantly decreased in size (1 of 5). One patient was lost to follow-up.

CONCLUSIONS

Macroadenoma-associated peritumoral cysts are rare, benign, and likely nonneoplastic fluid collections that do not represent neoplasm. These cysts display a predictable pattern of hyperintensity on T1-weighted, T2-weighted, and FLAIR sequences and do not enhance. They most likely represent proteinaceous CSF in a sulcus or cistern that becomes trapped (encysted) by anterolateral extension of unusually large macroadenomas. Peritumoral cysts may facilitate resection of the associated macroadenoma by providing a cleavage plane.

Pathology of the Nervous System in Von Hippel-Lindau Disease

Von Hippel-Lindau (VHL) disease is a tumor syndrome that frequently involves the central nervous system (CNS). It is caused by germline mutation of the VHL gene. Subsequent VHL inactivation in selected cells is followed by numerous well-characterized molecular consequences, in particular, activation and stabilization of hypoxia-inducible factors HIF1 and HIF2. The link between VHL gene inactivation and tumorigenesis remains poorly understood. Hemangioblastomas are the most common manifestation in the CNS; however, CNS invasion by VHL disease-associated endolymphatic sac tumors or metastatic renal cancer also occur, and their differentiation from primary hemangioblastoma may be challenging. Finally, in this review, we present recent morphologic insights on the developmental concept of VHL tumorigenesis which is best explained by pathologic persistence of temporary embryonic progenitor cells.

Early-stage hemangioblastoma presenting as a small lesion with significant edema in the cerebellum

Hemangioblastomas are benign tumors that are frequently associated with peritumoral cysts; however, their early characteristics before cyst formation remain unclear. In this article, the authors present a novel case of a cerebellar hemangioblastoma presenting as a small solid lesion with significant edema. Surgery was performed to resect the tumor, and a follow-up magnetic resonance imaging scan revealed complete excision of the mass and resolution of the cerebellar edema. Histological examination confirmed that the lesion was a hemangioblastoma. This is the only report in the literature to describe the imaging and histopathologic characteristics of an initial hemangioblastoma in the cerebellum.

Inhibitory effects of dunning rat prostate tumor fluid on proliferation of the metastatic MAT-LyLu cell line

Tumor fluid accumulation occurs in both human cancer and experimental tumor models. Solid tumors show a tendency to tumor fluid accumulation because of their anatomical and physiological features and this may be influenced by molecular factors. Fluid accumulation in the peri-tumor area also occurs in the Dunning model of rat prostate cancer as the tumor grows. In this study, the effects of tumor fluids that were obtained from Dunning prostate tumor-bearing Copenhagen rats on the strongly metastatic MAT-LyLu cell line were investigatedby examining the cell's migration and tumor fluid's toxicity and the kinetic parameters such as cell proliferation, mitotic index, and labelling index. In this research, tumor fluids were obtained from rats injected with 25105 MAT- LyLu cells and treated with saline solution, and 200 nM tetrodotoxin (TTX), highly specific sodium channel blocker was used. Sterilized tumor fluids were added to medium of MAT-LyLu cells with the proportion of 20% in vitro. Consequently, it was demonstrated that Dunning rat prostate tumor fluid significantly inhibited proliferation (up to 50%), mitotic index, and labeling index of MAT-LyLu cells (up to 75%) (p<0.05) but stimulated the motility of the cells in vitro.

Development of a small solid cerebellar haemangioblastoma into a large pseudocyst with a mural nodule in a patient without VHL; the importance of regular follow-up

Haemangioblastomas (HBLs) are rare central nervous system tumours accounting for only 1.2-2.5% of all intracranial tumours. While most HBLs occur sporadically, 36-40% of cases are associated with von Hippel-Lindau (VHL) syndrome. Owing to its benign nature, sporadic cases are usually detected only when symptoms occur due to mass effect. Thus, the natural history of HBLs has only been studied in association with VHL syndrome. We present a case of sporadic HBL with a rapid evolution of its small nodule into an enlarging mural nodule with a large pseudocyst that resulted in increased intracranial pressure. Craniotomy for complete tumour removal was performed and the patient fully recovered. This case implies a regular follow-up of HBL might be mandatory even in patients without VHL.

Pathological and Clinical Features and Management of Central Nervous System Hemangioblastomas in von Hippel-Lindau Disease

Central nervous system (CNS) hemangioblastoma is the most common manifestation of von Hippel-Lindau (VHL) disease. It is found in 70-80% of VHL patients. Hemangioblastoma is a rare form of benign vascular tumor of the CNS, accounting for 2.0% of CNS tumors. It can occur sporadically or as a familial syndrome. CNS hemangioblastomas are typically located in the posterior fossa and the spinal cord. VHL patients usually develop a CNS hemangioblastoma at an early age. Therefore, they require a special routine for diagnosis, treatment and follow-up. The surgical management of symptomatic tumors depend on many factors such as symptom, location, multiplicity, and progression of the tumor. The management of asymptomatic tumors in VHL patients are controversial since CNS hemangioblastomas grow with intermittent quiescent and rapid-growth phases. Preoperative embolization of large solid hemangioblastomas prevents perioperative hemorrhage but is not necessary in every case. Radiotherapy should be reserved for inoperable tumors. Because of complexities of VHL, a better understanding of the pathological and clinical features of hemangioblastoma in VHL is essential for its proper management.

Characterization of the blood-brain barrier of metastatic and primary malignant neoplasms

OBJECT

The astrocytic contribution to the blood-brain barrier (BBB) in metastatic and primary malignant brain tumors is not well understood. To better understand the vascular properties associated with metastatic and primary malignant brain tumors, the authors systematically analyzed the astrocytic component of the BBB in brain neoplasms.

METHODS

Twelve patients who underwent resection of metastatic or primary brain neoplasms (4 metastatic lesions, 2 low-grade astrocytomas, 2 anaplastic astrocytomas, and 4 glioblastoma multiforme) were included. Clinical, MRI, operative, histopathological and immunohistochemical (glial fibrillary acidic protein [GFAP], CD31, and aquaporin 4 [AQ4]) findings were analyzed.

RESULTS

Intratumoral regions of MRI enhancement corresponded with breakdown of the normal astrocyte-endothelial cell relationship in the BBB in metastatic deposits and malignant gliomas. Metastases demonstrated lack of perivascular GFAP and AQ4 on CD31-positive intratumoral vessels. At the metastasis-brain interface, normalization of GFAP and AQ4 staining associated with intraparenchymal vessels was observed. Intratumoral vasculature in enhancing regions of high-grade gliomas revealed gaps in GFAP and AQ4 staining consistent with disintegration of the normal astrocyte-endothelial cell association in the BBB. Intratumoral vasculature in low-grade and nonenhancing regions of high-grade gliomas maintained the normal astrocyte-endothelial cell relationship seen in an intact BBB, with GFAP- and AQ4-positive glial processes that were uniformly associated with the CD31-positive vasculature.

CONCLUSIONS

Regions of MRI enhancement in metastatic and primary malignancies correspond to areas of breakdown of the physiological astrocyte-endothelial cell relationship of the BBB, including loss of normal perivascular astrocytic architecture on GFAP and AQ4 immunohistochemistry. Nonenhancing areas are associated with preservation of the normal astrocyte-endothelial cell relationship of the intact BBB.

Nervous system involvement in von Hippel-Lindau disease: pathology and mechanisms

Patients with von Hippel-Lindau disease carry a germline mutation of the Von Hippel-Lindau (VHL) tumor-suppressor gene. We discuss the molecular consequences of loss of VHL gene function and their impact on the nervous system. Dysfunction of the VHL protein causes accumulation and activation of hypoxia inducible factor (HIF) which can be demonstrated in earliest stages of tumorigenesis and is followed by expression of VEGF, erythropoietin, nitric oxide synthase and glucose transporter 1 in VHL-deficient tumor cells. HIF-independent functions of VHL, epigenetic inactivation of VHL, pVHL proteostasis, and links between loss of VHL function and developmental arrest are also described. A most intriguing feature in VHL disease is the occurrence of primary hemangioblastic tumors in the nervous system, the origin of which has not yet been entirely clarified, and current hypotheses are discussed. Endolymphatic sac tumors may extend into the brain, but originally arise from proliferation of endolymphatic duct/sac epithelium; the exact nature of the proliferating epithelial cell, however, also has remained unclear, as well as the question why tumors almost consistently develop in the intraosseous portion of the endolymphatic sac/duct only. The epitheloid clear cell morphology of both advanced hemangioblastoma and renal clear cell carcinoma can make the differential diagnosis challenging, recent developments in immunohistochemical differentiation are discussed. Finally, metastasis to brain may not only be caused by renal carcinoma, but may derive from VHL disease-associated pheochromocytoma/paraganglioma, or pancreatic neuroendocrine tumor.

Midline basifrontal solid hemangioblastoma in non von hippel lindau syndrome patient

Supratentorial location of hemangioblastoma is very rare. The authors report a case a 45 year old female who had sporadic solid supratentorial hemangioblastoma and who made a complete recovery following gross total removal of the tumor.

Effect of pregnancy on hemangioblastoma development and progression in von Hippel-Lindau disease

OBJECT

Prior cases suggest that pregnancy increases the development and progression of CNS hemangioblastomas and/or peritumoral cysts. To determine the effect of pregnancy on CNS hemangioblastomas and peritumoral cysts, the authors prospectively evaluated serial clinical and imaging findings in patients with von Hippel-Lindau (VHL) disease who became pregnant and compared findings during pregnancy to findings in the same patients when they were not pregnant as well as to findings from a cohort of VHL patients who did not become pregnant.

METHODS

Female VHL disease patients enrolled in a prospective natural history study who were of reproductive age (16-35 years at study entrance) were included. Analysis of serial clinical and imaging findings was performed.

RESULTS

Thirty-six consecutive female VHL disease patients harboring 177 hemangioblastomas were included (mean follow-up [± SD] 7.5 ± 2.3 years). Nine patients (25%) became pregnant (pregnancy cohort). The mean rates of development of new hemangioblastomas and peritumoral cysts in these women during pregnancy (0.4 ± 0.4 tumors/year; 0.1 ± 0.2 cysts/year) did not differ significantly (p > 0.05) from the mean rates in the same group during nonpregnant periods (0.3 ± 0.4 tumors/year; 0.1 ± -0.1 cysts/year) or from the rate in the 27 patients who did not become pregnant (the no-pregnancy cohort: 0.3 ± 0.5 tumors/year; 0.1 ± 0.2 cysts/year). Hemangioblastoma growth rates were similar (p > 0.05) during pregnancy (mean 29.8% ± 42.7% increase in volume per year) compared with during nonpregnant periods (41.4% ± 51.4%) in the pregnancy cohort and the no-pregnancy cohort (34.3% ± 55.3%). Peritumoral cyst growth rates during pregnancy (571.0% ± 887.4%) were similar (p > 0.05) to those of the no-pregnancy cohort (483.9% ± 493.9%), but the rates were significantly higher for women in the pregnancy cohort during nonpregnant periods (2373.6% ± 3392.9%; p < 0.05 for comparison with no-pregnancy cohort). There was no significant difference (p > 0.05) in the need for resection or the mean age at resection between the pregnancy (28% of hemangioblastomas in cohort; mean patient age at resection 30.2 ± 2.6 years) and no-pregnancy cohorts (19%; 32.3 ± 5.6 years).

CONCLUSIONS

Pregnancy is not associated with increased hemangioblastoma or peritumoral cyst development or progression in patients with VHL disease.

Von Hippel-Lindau: how a rare disease illuminates cancer biology

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant syndrome (1/36,000 live births) with highly penetrance that predispose to the development of a panel of highly vascularized tumors (model of tumoral angiogenesis). Main manifestations include central nervous system (CNS) and retinal haemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), phaeochromocytomas and pancreatic neuroendocrine tumors. RCC has become the first potential cause of mortality and VHL disease is the main cause of inherited RCC. The disease is caused by germline mutations in the VHL tumor-suppressor gene that plays a major role in regulation of the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. VHL has also major HIF-independent functions, specially in regulation of primary cilium, extracellular matrix and apoptosis. Somatic inactivation of the VHL gene is the main molecular event in most sporadic RCC and the treatment of advanced RCC has been revolutionized by targeted therapy with drugs that block angiogenesis. These drugs are now in first line in metastatic sporadic RCC and have shown promising results for RCC, pancreatic neuroendocrine tumors and malignant pheochromocytomas in VHL patients.