Case report: Obstructive azoospermia as the first presentation of Von Hippel-Lindau disease

We report the case of a 38-year-old man whose diagnostic workup for primary infertility led to the discovery of obstructive azoospermia due to bilateral papillary cystadenoma of the epididymis (PCE). Given the rarity of this finding and because PCE could be a manifestation of Von Hippel-Lindau disease (VHL), although the patient had no family or personal history of VHL, the VHL gene was tested, and a known pathogenetic variant (c.464-1G>A; p.)? was found. Screening for other Von Hippel-Lindau disease-associated neoplasms revealed bilateral retinal capillary hemangioblastomas, clear cell renal cell carcinoma, and multiple pancreatic cysts. In this case, an accurate diagnostic workup for male infertility allowed the detection of a rare life-threatening syndrome, already presenting with several silent neoplasms. For this reason, this case report may be useful for reproductive medicine specialists in the management of male infertility.

Assessing the efficacy and safety of hemangioblastoma embolization: A comprehensive systematic review and meta-analysis

BACKGROUND

Hemangioblastomas (HBs) are highly vascular tumors linked to substantial morbidity and mortality. Recently, interventional neuroradiology has evolved rapidly, spurring interest in preoperative embolization as a possible HB treatment.

PURPOSE

This study evaluates the effectiveness and safety of preoperative embolization in managing HB.

METHODS

Adhering to PRISMA guidelines, this meta-analysis considered randomized and nonrandomized studies meeting specific criteria, encompassing intracranial HB and preoperative embolization. Primary outcomes were preoperative embolization efficacy and safety. Complications were classified as major (cerebellar ischemia, ischemic strokes, intratumoral hemorrhage, subarachnoid hemorrhage) and minor (transient nystagmus, slight facial nerve palsy, nausea, transient dysarthria, hemiparesis, hemisensory impairment, thrombotic complications, extravasation).

RESULTS

Thirteen studies involving 166 patients with preoperative embolization before HB resection were included. Two studies using the Glasgow Outcome Scale (GOS) showed 5 patients with good recovery, 6 with moderate disability, and 3 with severe disability. Major complications occurred in 1% (95% CI: 0% to 3%), and minor complications occurred in 1% (95% CI: 0% to 4%). Intraoperative blood loss during resection was estimated at 464.29 ml (95% CI: 350.63 ml to 614.80 ml).

CONCLUSION

Preoperative embolization holds promise in reducing intraoperative bleeding risk in neurosurgical intracranial HB treatment, primarily due to its low complication rates. Nonetheless, additional research and larger-scale studies are essential to establish its long-term efficacy and safety. These findings highlight preoperative embolization as a valuable tool for HB management, potentially enhancing future patient outcomes.

Case Report: Aggressive neural crest tumors in a child with familial von Hippel Lindau syndrome associated with a germline VHL mutation (c.414A>G) and a novel KIF1B gene mutation

Introduction

Von Hippel Lindau (VHL) syndrome is caused by an autosomal dominant hereditary or sporadic germline mutation of the VHL gene with more than five hundred pathogenic mutations identified. Pheochromocytomas and rarely paragangliomas occur in 10-50% of patients with VHL syndrome usually around 30 years of age and exceptionally before the age of 10.

Case presentation

We diagnosed a 9-year-old girl of normal appearance and severe refractory hypertension, with a norepinephrine-secreting pheochromocytoma related to VHL syndrome due to a known familial germline heterozygous mutation of VHL gene (c.414A>G), also present in three members of her family. At age 13, a pelvic tumor and a left adrenal pheochromocytoma that showed to be multi-metastatic to both lungs were discovered in the patient leading to left adrenalectomy and pelvic tumor resection. In addition to the germline VHL gene mutation, blood analysis using Next Generation Sequencing identified a novel heterozygous germline mutation of the KIF1B gene (c.3331_3332del; p.Asn1111Glnfs*21), which is only present in the girl and not the other family members. The patient is currently under steroid substitution therapy and leads a normal life.

Discussion

This family is notable by the early age of onset of multiple neural crest tumors associated with a high propensity for malignancy and metastatic spread. Most reports in the literature associated the VHL mutation with a later onset in adulthood and a benign course, which contrast with our findings and question the role of this mutation in the phenotype expressed in this kindred. Also, the presence of concomitant mutations in two susceptibility genes for neural crest tumors poses the question of their respective roles in the development of tumors in this family. Our familial case description illustrates the potential for systematic use of targeted Next Generation Sequencing with multi-gene panels in patients with neural crest tumors to confirm the role of known susceptibility genes as well as identifying new ones, but also to contribute to comprehensive databases on gene variants and their phenotypic counterparts in this specific area of medicine.

Systematic Potency and Property Assessment of VHL Ligands and Implications on PROTAC Design

Herein, we describe a systematic SAR- and SPR-investigation of the peptidomimetic hydroxy-proline based VHL-ligand VH032, from which most to-date published VHL-targeting PROTACs have been derived. This study provides for the first time a consistent data set which allows for direct comparison of structural variations including those which were so far hidden in patent literature. The gained knowledge about improved VHL binders was used to design a small library of highly potent BRD4-degraders comprising different VHL exit vectors. Newly designed degraders showed favorable molecular properties and significantly improved degradation potency compared to MZ1.

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

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

Differential HIF2α Protein Expression in Human Carotid Body and Adrenal Medulla under Physiologic and Tumorigenic Conditions

Hypoxia-inducible factors (HIF) 2α and 1α are the major oxygen-sensing molecules in eukaryotic cells. HIF2α has been pathogenically linked to paraganglioma and pheochromocytoma (PPGL) arising in sympathetic paraganglia or the adrenal medulla (AM), respectively. However, its involvement in the pathogenesis of paraganglioma arising in the carotid body (CB) or other parasympathetic ganglia in the head and neck (HNPGL) remains to be defined. Here, we retrospectively analyzed HIF2α by immunohistochemistry in 62 PPGL/HNPGL and human CB and AM, and comprehensively evaluated the HIF-related transcriptome of 202 published PPGL/HNPGL. We report that HIF2α is barely detected in the AM, but accumulates at high levels in PPGL, mostly (but not exclusively) in those with loss-of-function mutations in VHL and genes encoding components of the succinate dehydrogenase (SDH) complex. This is associated with upregulation of EPAS1 and the HIF2α-regulated genes COX4I2 and ADORA2A. In contrast, HIF2α and HIF2α-regulated genes are highly expressed in CB and HNPGL, irrespective of VHL and SDH dysfunctions. We also found that HIF2α and HIF1α protein expressions are not correlated in PPGL nor HNPGL. In addition, HIF1α-target genes are almost exclusively overexpressed in VHL-mutated HNPGL/PPGL. Collectively, the data suggest that involvement of HIF2α in the physiology and tumor pathology of human paraganglia is organ-of-origin-dependent and HIF1α-independent.

Familial multiple sclerosis in patients with Von Hippel-Lindau disease

Background

Multiple sclerosis (MS) is a progressive autoimmune demyelinating disorder. Recent studies suggest that a combination of genetic susceptibility and environmental insult contributes to its pathogenesis. Many candidate genes have been discovered to modulate susceptibility for developing MS by genome wide association studies (GWAS); these include major histocompatibility complex (MHC) genes and non-MHC genes. MS cases in the context of genetic diseases may provide different approaches and clues towards identifying novel genes and pathways involved in MS pathogenesis. Here, we present a case series of two related patients with concomitant Von Hippel-Lindau disease (VHLD) and MS.

Case presentation

We present two patients, a mother (case 1) and daughter (case 2), who developed superimposed relapsing-remitting multiple sclerosis in the background of the autosomal dominant genetic disorder VHLD. Several tumors characteristic of VHLD developed in both cases with pancreatic and renal neoplasms and cerebellar hemangioblastomas. In addition, both patients developed clinical symptoms consistent with multiple sclerosis, supported by radiologic lesions disseminating in time and space.

Conclusion

Though non-MHC susceptibility genes remain elusive in MS, we present the striking finding of superimposed multiple sclerosis in a mother and daughter with VHLD. The VHL gene is known to be the primary regulator of Nrf2, the well-established target of the FDA-approved therapeutic dimethyl fumarate. These cases provide support for further studies to determine whether VHLD pathway related genes represent a novel genetic link in multiple sclerosis.

Gut HIF2α signaling is increased after VSG, and gut activation of HIF2α decreases weight, improves glucose, and increases GLP-1 secretion

Gastric bypass and vertical sleeve gastrectomy (VSG) remain the most potent and durable treatments for obesity and type 2 diabetes but are also associated with iron deficiency. The transcription factor HIF2α, which regulates iron absorption in the duodenum, increases following these surgeries. Increasing iron levels by means of dietary supplementation or hepatic hepcidin knockdown does not undermine the effects of VSG, indicating that metabolic improvements following VSG are not secondary to lower iron levels. Gut-specific deletion of Vhl results in increased constitutive duodenal HIF2α signaling and produces a profound lean, glucose-tolerant phenotype that mimics key effects of VSG. Interestingly, intestinal Vhl deletion also results in increased intestinal secretion of GLP-1, which is essential for these metabolic benefits. These data demonstrate a role for increased duodenal HIF2α signaling in regulating crosstalk between iron-regulatory systems and other aspects of systemic physiology important for metabolic regulation.

Bariatric surgery remains the most potent treatment for obesity and type 2 diabetes but also reduces iron levels. Evers et al. find that the machinery for absorbing iron is activated after VSG. Activation of this machinery recapitulates multiple effects of VSG. These findings may lead to less invasive therapies.

Clinical and Laboratory Characteristics of a Large Iranian Kindred Afflicted with Von Hippel Lindau Disease

BACKGROUND

Von Hippel Lindau (VHL) disease is a hereditary disorder characterized by the development of benign or malignant tumors in the brain, spinal cord, eyes, adrenal medulla, kidney, pancreas, and many other organs. Advances in molecular diagnosis have led to the identification of the affected members of families at earlier stages. We present the clinical, laboratory, and genetic characteristics of five generations of a large Iranian kindred with VHL.

METHODS

The proband, a 52-year-old Iranian man, was recognized with VHL. All family members underwent clinical, laboratory, imaging, and genetic evaluation. Medical files and histopathology reports of patients who had been operated on before were also reviewed. Diagnosis of the disease was based on clinical findings, positive family history of VHL, and development of a central nervous system or retinal hemangioblastoma or pheochromocytoma.

RESULTS

Based on diagnostic criteria, our initial evaluations revealed that 10 members of the family had already been affected by the disease. Among them, nine had pheochromocytoma, and one had retinal hemangioblastoma. There was no case of kidney tumors among the kindred.

CONCLUSIONS

Study results show the high penetrance of the disease and focus on the large burden imposed by the disease on the health and quality of life of patients afflicted with the disease, emphasizing the importance of surveillance from early childhood for detection and management of the disease as early as possible.

Linear accelerator stereotactic radiosurgery can modulate the clinical course of Hemangioblastoma: Case series and review of the literature

Hemangioblastomas (HB) are benign low grade vascular tumors most frequently occurring in the cerebellum, brain stem, and spinal cord. Often associated with Von Hippel Lindau disease (VHL), the lesions are often multifocal requiring complex resection and are difficult to control. Linear Accelerator (LINAC) Stereotactic Radiosurgery (SRS) has been demonstrated to provide additional tumor control. In this case series, we present our multi-center experience utilizing LINAC SRS in fourteen patients with 23 lesions. We observed a tumor control rate of 87% and found interval changes in the peritumoral enhancement to correlate with treatment outcome. In our study, SRS treatment was also well-tolerated in both cystic and noncystic patients with multifocal disease. Disease control was achieved in all but three patients post-resection and no longitudinal radiation-induced secondary malignancy was observed. SRS response correlated highly with lesion size and radiation dose. We conclude that LINAC SRS is safe and effective for patients with HB and should be considered in addition to surgery in asymptomatic, VHL patients, deep seated lesions and isolated lesions.

Resection of a conus medullaris hemangioblastoma: Case report

Background

Conus medullaris tumors are rare, as the majority of all spinal cord tumors occur in the cervical and thoracic regions. Hemangioblastomas of the spinal cord account for 3%-4% of all intramedullary spinal cord tumors and can be sporadic or associated with von Hippel-Lindau disease. There are only fourteen cases of conus medullaris hemangioblastomas published in the literature, herein we present the fifteenth.

Case description

A 44-year old male with von Hippel Lindau disease presented with worsening bilateral lower extremity weakness, gait imbalance as well as absent perineal and genital sensation with weak voluntary anal contraction. MRI demonstrated multiple stable spinal tumors and a 6 mm conus medullaris hemangioblastoma with growth and a new peri-tumoral cyst. The patient underwent uncomplicated surgical resection with appreciable improvement in perineal sensation and sphincteric control during post-operative course.

Conclusions

Timely resection of conus medullaris tumors can provide symptomatic relief and prevent the progression of devastating neurological deficits. Careful microsurgical dissection with appropriate patient selection allows for safe resection of conus medullaris tumors.

Is ultra wide-field retinal imaging alone appropriate for retinal angioma screening in lower risk subjects attending Von Hippel-Lindau (VHL) clinics?

Purpose: To determine if non-mydriatic ultra wide-angle digital retinal imaging alone is effective for screening subjects considered to be at 50% or lower risk for developing retinal angiomas.Methods: Digital records and retinal images of subjects attending a regional Von-Hippel-Lindau disease multi-disciplinary clinic over a 12 month period were reviewed. Individuals were stratified for risk of developing retinal angiomas on the basis of age, clinical features and genetic risk. The image quality and necessity for subsequent mydriatic fundoscopy were assessed.Results: Eighty subjects from 55 pedigrees attended the VHL clinic over 12 months. Of these, 44 (55%) were considered to be at lower risk for retinal angiomatosis: 34 (77%) because they had reached at least 30 years of age without developing an angioma, 16 with a presenting solitary tumour of the type associated with VHL but no identifiable gene mutation, and 12 with a family history giving them a 50% risk of carrying a gene mutation. Eighteen patients fulfilled two low risk criteria. All were able to comply with imaging but poor image quality (limited view of the inferior retinal far-periphery) required subsequent dilated fundoscopy in five (6%) eyes of three patients.Conclusions: Non-mydriatic ultra wide-field retinal imaging enabled satisfactory assessment in over 95% of lower-risk VHL subjects. Virtual clinics or remote imaging of lower-risk subjects may improve both the efficiency and flexibility in the provision of multi-disciplinary VHL services and the patient experience.

Glucocorticoids promote Von Hippel Lindau degradation and Hif-1α stabilization

Glucocorticoid (GC) and hypoxic transcriptional responses play a central role in tissue homeostasis and regulate the cellular response to stress and inflammation, highlighting the potential for cross-talk between these two signaling pathways. We present results from an unbiased in vivo chemical screen in zebrafish that identifies GCs as activators of hypoxia-inducible factors (HIFs) in the liver. GCs activated consensus hypoxia response element (HRE) reporters in a glucocorticoid receptor (GR)-dependent manner. Importantly, GCs activated HIF transcriptional responses in a zebrafish mutant line harboring a point mutation in the GR DNA-binding domain, suggesting a nontranscriptional route for GR to activate HIF signaling. We noted that GCs increase the transcription of several key regulators of glucose metabolism that contain HREs, suggesting a role for GC/HIF cross-talk in regulating glucose homeostasis. Importantly, we show that GCs stabilize HIF protein in intact human liver tissue and isolated hepatocytes. We find that GCs limit the expression of Von Hippel Lindau protein (pVHL), a negative regulator of HIF, and that treatment with the c-src inhibitor PP2 rescued this effect, suggesting a role for GCs in promoting c-src-mediated proteosomal degradation of pVHL. Our data support a model for GCs to stabilize HIF through activation of c-src and subsequent destabilization of pVHL.

[Intramedullary hemangioblastomas]

AIM AND BACKGROUND

Intramedullary hemangioblastomas are rare lesions representing 1 to 5% of spinal tumors. The aim of this study was to review our experience with the surgical management of intramedullary hemangioblastomas.

MATERIALS AND METHODS

We performed a retrospective analysis of all the patients with intramedullary hemangioblastomas operated on between 1993 and 2011 in our department. All the patients were screened for Von Hippel Lindau disease. The minimum follow-up was 3 years. The clinical presentation, radiological findings, surgical procedure and outcomes were recorded and analyzed.

RESULTS

Our consecutive series included 59 patients with a total of 65 tumors. The mean age at diagnosis was 38 years. Forty-two patients (72.5%) had Von Hippel Lindau disease. The main symptom was pain (58% of cases). The most common location was cervical spinal cord. The average size was 15mm. The resection was complete in 95% cases resulting in clinical improvement in 12% cases, stability in more than 86% of cases and deterioration in less than 2% cases.

CONCLUSION

All patients with intramedullary hemangioblastoma should have a screening for the Von Hippel Lindau disease and if the diagnosis is correct, close monitoring should be initiated. Surgical removal is strongly advised in cases of neurological deficits or radiological progression of the tumour.

The utility of cortical-sparing adrenalectomy in pheochromocytomas associated with genetic syndromes

Management of pediatric patients with pheochromocytomas associated with genetic syndromes, such as Von Hippel-Lindau (VHL) disease, is complex owing to the need for continuous surveillance, high rates of recurrence, multiple operations during childhood, and the possibility of lifelong exogenous steroid replacement. We report the successful treatment of two siblings with VHL who underwent a total of six cortical-sparing procedures without requiring steroid therapy.