Insights into the pathogenesis of neurofibromatosis 1 vasculopathy

Unveiling the uncommon: Giant internal jugular vein aneurysm in a neurofibromatosis patient: A case report

Neurofibromatosis Type 1 (NF1) is a rare autosomal dominant disorder that has a wide array of clinical manifestations. NF1 Vasculopathies constitute 0.4% to 6.4% of the findings and they often develop in the arterial circulation while venous involvement is rare. We present a case of a 73-year-old male with NF1 with an incidental finding of right neck swelling for 2 months. Different radiological modalities were performed, identifying the lesion as an internal jugular vein aneurysm. The patient was managed conservatively as he was asymptomatic in relation to the swelling. NF1 venous vasculopathies are rare but they have detrimental consequences such as rupture and severe hemorrhage in view of the fragility of the aneurysmal wall and the infiltration of the neurofibroma into the vessel. Hence, high clinical suspicion and selective imaging and follow-up is advisable for physicians.

The Nf1-Q181X point mutation induces M2 macrophage polarization via the AKT/STAT pathway to promote smooth muscle cell proliferation and migration

BACKGROUND

Increased case reports have shown that patients with NF1 have an increased risk of extensive vascular vasculopathy. Previous studies demonstrated the presence of macrophages and smooth muscle cells in the neoplastic intima of carotid arteries after injury in Nf1+/- mice. However, whether NF1 gene mutations affect macrophage polarization and macrophage-smooth muscle cell interactions remains to be elucidated.

METHODS

Scratch assay and transwell assay were utilized to detect cell migration ability. The dye 2',7'dichlorofluorescin diacetate and neutral red stain were used to assess intracellular ROS production and cell phagocytosis function, respectively. Proteins and mRNA expression were determined by western blot, RT-qPCR, and immunofluorescence. Finally, the macrophage (MAC) and vascular smooth muscle cell (VSMC) co-culture system was used to detect cellular crosstalk.

RESULTS

Cell function assays confirmed that the Nf1-Q181X point mutation attenuated the phagocytosis of bone marrow-derived macrophages (BMDMs) and promoted the migration and ROS production of BMDMs. Moreover, we found that the Nf1-Q181X point mutation inhibited M1 but promoted M2 macrophage polarization by down-regulating p38, ERK, and JNK and up-regulating the Akt/STAT3 signaling pathway, respectively. Furthermore, in the MAC-VSMC co-culture system, we demonstrated that Nf1-Q181X point mutation-activated M2 BMDMs promoted proliferation and migration of VSMCs and induced the transformation of VSMCs from contractile phenotype to synthetic phenotype.

CONCLUSION

The findings suggest that the Nf1-Q181X point mutation can mediate macrophage polarization and promote smooth muscle cell proliferation and migration, providing clinical clues for the treatment of NF1-complicated vasculopathy.

Surgical revascularization as a procedure to prevent neurological complications in children with moyamoya syndrome associated with neurofibromatosis I: a single institution case series

BACKGROUND

The optimal timing and surgical approach for surgical revascularization in patients with moyamoya syndrome (MMS) associated with neurofibromatosis type I (NF1) remain so far elusive. We aimed to compare the long-term clinical, radiological, and cognitive effects of different revascularization procedures in a pediatric cohort of NF1-associated MMS.

METHODS

We reviewed the clinical, radiological, and surgical data of 26 patients with NF1-associated MMS diagnosed at our institution between 2012 and 2022, at the clinical onset and last follow-up.

RESULTS

Indirect bypasses were performed in 12/26 patients (57.1%), while combined direct and indirect procedures in 9/26 subjects (42.9%); 5 patients did not undergo surgery. Through logistic regression analysis, pathological Wechsler Intelligence Scale for Children (WISC) at onset was found to be associated with symptom improvement at 1-year follow up (p = 0.006). No significant differences were found in long-term neurocognitive outcome and stroke rate in patients receiving combined or indirect bypass (p > 0.05).

CONCLUSIONS

Currently, whether combined or indirect bypass should be considered the treatment of choice in pediatric patients with NF1-associated MMS remains unclear, as well as the optimal time approach. In our series, no significant differences were found in long-term neurocognitive outcome and stroke rate between patients treated with either of these two approaches. Clinical evidence supports the crucial role of early diagnosis and surgical revascularization in subjects with MMS-associated NF1, even in case of mildly symptomatic vasculopathy. This allows to achieve a good long-term outcome with improved intellectual function and prevention of stroke and seizure in these patients.

A life-threatening, massive subcutaneous hematoma caused by trauma in a patient with neurofibromatosis type 1: a case report and literature review

Background

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease that can give rise to the formation of vascular lesions in affected individuals. These lesions, whether occurring spontaneously or as a result of trauma, have the potential to cause severe and even fatal hemorrhage.

Case description

We presented a case demonstrating the most extensive hematoma ever documented in a patient with NF1, resulting from a minor trauma. He experienced hemodynamic instability due to severe anemia. Arteriography revealed a rupture in the intercostal artery, which was successfully treated through interventional embolization to stop the hemorrhage. Additionally, we implemented a refined surgical approach, beginning with suturing, followed by the meticulous resection of necrotic and aberrant tissues, thereby markedly diminishing bleeding.

Conclusion

Minor trauma may cause severe bleeding in patients with NF1, which can be life-threatening. Timely diagnosis of NF1 and effective hemostatic techniques are key to successful treatment.

Myocardial Infarction and Coronary Anomalies in a 25-Year-Old Neurofibromatosis Type 1 Patient

A 25-year-old male with neurofibromatosis type 1 presented with acute ST-segment elevation myocardial infarction. Coronary imaging revealed an aberrant right coronary anatomy, ectatic coronary arteries, and significant stenosis. Based on previous literature and clinical presentation, this case highlights the potential role of neurofibromatosis in the pathogenesis of coronary artery disease.

Ruptured Occipital Artery Aneurysm Following Craniotomy in a Patient with Neurofibromatosis Type 1: Case Report

Objective

Neurofibromatosis type 1 (NF1) is associated with vascular fragility, which results in aneurysms, arteriovenous fistulas, and dissections. Here, we describe a case of endovascular treatment of a ruptured occipital artery aneurysm that occurred after a craniotomy in a patient with NF1.

Case Presentation

A 46-year-old man with a history of NF1 underwent a right lateral suboccipital craniotomy to remove a cavernous hemangioma in the right middle cerebellar peduncle. Severe bleeding occurred in the occipital artery during the craniotomy. Due to vessel fragility, coagulation and ligation were not possible, and pressure hemostasis was achieved using cellulose oxide and fibrin glue. On postoperative day 12, the patient developed a sudden swelling on the right side of the neck as well as tracheal compression. Contrast-enhanced CT revealed a ruptured aneurysm in the right occipital artery. Transarterial embolization was performed under general anesthesia the same day. Right external carotid angiography showed an 18-mm-diameter fusiform aneurysm in the occipital artery. The aneurysm ruptured inferiorly to form a large pseudoaneurysm with significant jet flow. An arteriovenous fistula was also observed in a nearby vein. A microcatheter was inserted into the fusiform aneurysm under proximal blood flow control, and embolization was performed using coils and N-butyl-2-cyanoacrylate.

Conclusion

Compared to surgical repair of ruptured occipital artery aneurysms, endovascular treatment appears to be safe, effective, minimally invasive, and rapid. Ruptured occipital artery aneurysms in NF1 patients can cause neck swelling and airway compression and should be recognized as a potentially lethal condition.

Successful revascularization using a saphenous vein for a ruptured brachial artery aneurysm in a patient with neurofibromatosis type I

Vasculopathy in patients with type 1 neurofibromatosis is known. Brachial artery aneurysms in patients with type 1 neurofibromatosis are rare, but any rupture can be extremely serious. A 56-year-old woman presented to our hospital with sudden pain in her right upper arm. Computed tomography revealed a ruptured brachial artery aneurysm, and operative reconstruction using a saphenous vein graft was performed. This is one of the few case reports of such successful revascularization using saphenous vein. The pathologic findings suggest neurogenic tumor invasion, and end-to-side anastomosis was effective in avoiding hemorrhagic complications.

Massive Hemorrhage Following Acupuncture Treatment in a Neurofibromatosis Type 1 Patient

Neurofibromatosis type 1 (NF1) is a genetic disorder involving multiple organs. Vascular involvement is a rare complication among NF1 patients. We report a case of a 59-year-old female NF1 patient who presented with a massive hematoma over the scapular area after undergoing acupuncture treatment. Contrast-enhanced CT and MRI demonstrated a slightly hyperdense mass measuring 24.2 × 10.3 cm in size, and multiple enlarged and tortuous malformed vessels were seen arising from the left subclavian artery. Arterial embolization and subsequent surgical mass resection were successfully performed. This case indicates that minor injuries such as acupuncture-related ones could cause severe hemorrhage in patients with vascular malformation related to NF1. Endovascular angiography and embolization proved to be effective in localizing the culprit vessel and stopping active bleeding in our patient.

Aneurysms involving the coronary arteries in a neonate with neurofibromatosis 1

Aneurysmal coronary artery disease (ACAD) has been reported rarely in patients with neurofibromatosis type 1 (NF1), mostly in adults. We report on a female newborn affected by NF1 with ACAD disclosed during investigation for an abnormal prenatal ultrasound along with a review of the previously reported cases. The proposita had multiple café-au-lait spots and had no cardiac symptoms. Echocardiography, and cardiac computed tomography angiography confirmed aneurysms on the left coronary artery, left anterior descending coronary artery, and of the sinus of Valsalva. Molecular analysis detected the pathogenic variant NM_001042492.3(NF1):c.3943C>T (p.Gln1315*). Literature findings on ACAD in NF1 indicated that this mostly occurs in males, showing predilection for the development of aneurysms at the left anterior descending coronary artery, and manifesting predominantly as acute myocardial infarction, inclusively in teenagers, though it may be also asymptomatic as in our case. This report documents the first case of ACAD in a patient with NF1 diagnosed at birth, emphasizing that its early diagnosis is essential to prevent potential life-threatening events attributable directly to coronary lesions.

Successful endovascular management for spontaneous hemothorax in a patient with neurofibromatosis Type1: A case report and review

INTRODUCTION AND IMPORTANCE

Neurofibromatosis Type 1 (NF1) is a rare autosomal dominant genetic disorder that affects multiple organs and systems, including the nervous system, integumentary system, and connective tissues. Spontaneous hemothorax occurs infrequently in patients with NF1 and is associated with high fatality rates. However, it is commonly overlooked or misdiagnosed.

CASE PRESENTATION

We present the case of a 29-year-old woman with NF1 who complained of chest pain and was detected with hemothorax on radiographic examination. No bleeding sites were identified following thrombectomy. The patient's condition deteriorated with conservative treatment over nine days, posing a potentially life-threatening risk. After a diagnostic evaluation using computerized tomography angiography (CTA) and digital subtraction angiography (DSA) of the neck vasculature, the patient was diagnosed with spontaneous rupture of the vertebral artery (VA) and subclavian artery (SuA) aneurysm. Following a multidisciplinary discussion and extensive investigations, the patient underwent successful endovascular treatment. A VIABAHN covered stent was implanted in the left SuA to overlay the emergent orifice. The endovascular treatment challenge due to the inaccessible of the proximal of left VA. To prevent retrograde flow into the VA aneurysm, the coils were used to embolize the left VA via the right vertebral artery-basilar artery (VA-BA) passage. The patient was alive at the 5-year follow-up without further complications.

CLINICAL DISCUSSION

The CTA examination led to the diagnosis of vascular rupture due to NF1, and endovascular treatment was performed to occlude the vascular lumen. There have been no recurrences during the five-year follow-up period.

CONCLUSION

Vasculopathy is the second leading cause of death in patients with NF1 after malignancy. Early diagnosis of spontaneous hemothorax in patients with NF1 is crucial, as misdiagnosis can result in missed treatment opportunities. CTA plays a vital role in preliminarily diagnosing the cause of spontaneous hemothorax, while endovascular treatment offers a new therapeutic option for such patients.

Neurofibromatosis type 1, fibromuscular dysplasia, and ischemic stroke: an association lost in time? A case report

Neurofibromatosis Type 1 (NF1) is a rare cause of ischemic stroke (IS) in the general population. We report a case of a young patient with NF1 in whom IS was caused by fibromuscular dysplasia. An angiographic study demonstrated occlusion in the right internal carotid artery (ICA), just after its origin, and the left ICA, just before the intracranial portion, and brain magnetic resonance imaging showed the limits of an area of brain infarction in the right frontoparietal region. Despite these concomitant neuroimaging findings, this association is rare, and it is difficult to establish the contribution to the outcome made by each of these diseases, which treatment is the best to implement, or what prognosis is.

Stent graft placement in anterior tibial artery pseudoaneurysm in a patient with type I neurofibromatosis: A case report

RATIONALE

Vascular involvement manifests as aneurysms, stenosis, and arteriovenous malformations in patients with type I neurofibromatosis (NF-I). Aneurysms are rare; however, the renal artery is the most common site. Herein, we report a rare case of stent graft placement in an anterior tibial artery (ATA) pseudoaneurysm in a patient with NF-I.

PATIENT CONCERNS

A 52-year-old woman with NF-1 was admitted to the emergency room with painful swelling in the left lower leg. At presentation, the patient's blood pressure was 100/60 mmHg and the hemoglobin level was 9 g/dL.

DIAGNOSES

Computed tomography scan revealed a small aneurysm arising from the left ATA and an adjacent large hematoma.

INTERVENTION

Stent graft placement was performed to treat ATA pseudoaneurysm.

OUTCOMES

After stent graft placement, the aneurysm disappeared and the distal flow was patent through the ATA.

LESSONS

Stent graft placement should be considered as another option for endovascular treatment in patients in whom coil embolization or surgery cannot be performed.

A novel NF1 mutation in a pediatric patient with renal artery aneurysm

BACKGROUND

Neurofibromatosis type 1 (NF1) is a neurocutaneous syndrome, due to heterozygous pathogenic variants in NF1 gene. The main clinical manifestations are multiple café au lait spots, axillary and inguinal freckling, cutaneous and plexiform neurofibromas, optic glioma, Lisch nodules and osseous lesions, such as sphenoid and tibial dysplasia. Vasculopathy is another feature of NF1; it consists of stenosis, aneurysms, and arteriovenous malformations, frequently involving renal arteries.

CASE PRESENTATION

We report on a 9-year-old girl with a novel mutation in NF1 gene and renal artery aneurysm, treated by coil embolization and complicated with hypertension.

CONCLUSION

Vasculopathy is a complication of NF1, affecting from 0.4 to 6.4% of patients with NF1. Among the vascular abnormalities, renal artery aneurysm is a rare manifestation, with only a few cases regarding adult patients and no pediatric reports described in current literature. The finding of a vascular abnormality in a specific site requires the evaluation of the entire vascular system because multiple vessels could be involved at the same time.

Hemorrhagic shock due to ruptured lower limb vascular malformation in a neurofibromatosis type 1 patient: A case report

BACKGROUND

Neurofibromatosis type 1 (NF-1) is a common autosomal dominant genetic disorder. It is characterized by café-au-lait spots and cutaneous neurofibromas. Although NF-1 typically involves the skin, nerves, bones, and eyes, vascular manifestation in the form of devastating hemorrhage can occur rarely.

CASE SUMMARY

We present the case of a 47-year-old female with NF-1 who had a ruptured right lower limb arterial malformation. She presented with sudden right lower limb swelling for two hours and symptoms of hemorrhagic shock on admission. The physical examination revealed a right lower limb presenting as elephantiasis and visible dark-brown pigmentation over a large area. Computed tomography angiography showed right lower limb arteriovenous malformation. Therefore, the patient underwent emergency right lower limb digital subtraction angiography (DSA) and vascular embolization after blood transfusions. However, after DSA, vascular embolization, and repeated blood transfusions, the anemia and right lower limb swelling and tenderness did not improve. As a result, the patient underwent right lower extremity above-knee amputation. After amputation, the patient's hemoglobin level improved significantly without blood transfusion, and she was discharged from the hospital after the incision healed. Postoperative pathological examination suggested neurogenic tumors. No other complications had occurred 1-year follow-up.

CONCLUSION

Vascular malformation and rupture are fatal complications of NF-1. Embolization may not provide complete relief, the patient might need to undergo neurofibroma resection or amputation.

Neurovascular complications in adults with Neurofibromatosis type 1: A national referral center experience

Neurofibromatosis type 1 (NF1) is associated with a range of vascular abnormalities. To assess the frequency, clinical and imaging spectrum of vascular complications in an adult cohort of NF1 patients, we reviewed 2068 adult NF1 patient records seen in our service between 2009 and 2019, to determine presence of vascular abnormalities, age at detection, associated symptoms and management. A literature review of the range of vascular abnormalities associated with NF1 was also undertaken. 1234 patients had magnetic resonance imaging cranial imaging. The frequency of vascular abnormalities associated with NF1 patients who had cranial imaging in this cohort was 3.5% (n = 43), the majority (n = 26, 60%) were symptomatic. Stroke and cerebral arterial stenosis were the commonest vascular complication. Eight patients (0.65%) had more than one type of vascular abnormality. One death due to a vascular complication was identified and significant morbidity resulted from other complications. We conclude that clinicians caring for patients with NF1 need to be cognizant that rapid onset of new neurological symptoms or signs may be the result of a vascular complication of NF1 and require urgent investigation and management, ideally within specialist teams who have experience of managing vascular complications of NF1.

Vertebral Artery Stenosis: A Narrative Review

Vertebral artery stenosis (VAS) is the cause of approximately 20% of ischemic strokes in the posterior circulation. There are several causes of vertebral artery stenosis, including atherosclerosis, calcification, dissections, fibromuscular dysplasia, giant cell arteritis, neurofibromatosis type 1, and bony compressions. The most common cause of VAS is atherosclerosis which is derived from the macrophage-induced oxidation of low-density lipoproteins (LDLs), alongside the accumulation of cholesterol. Calcification of the vertebral artery occurs when there is excess calcium and phosphate deposition in the vessel. Dissection of the vertebral artery can lead to the formation of a hematoma causing stenosis of the vertebral artery. Fibromuscular dysplasia can result in stenosis due to the deposition of collagen fibers in the tunica media, intima, or adventitia. Giant cell arteritis, an autoimmune disorder, causes inflammation of the internal elastic membrane resulting in eventual stenosis of the artery. Neurofibromatosis type 1, an autosomal dominant disorder, results in the stenosis of the vertebral artery due to the altered function of neurofibromin. Mechanical compression of the vertebral artery by bone can also cause stenosis of the vertebral artery. Digital subtraction angiography (DSA) is considered the current gold standard in diagnosing vertebral artery stenosis; however, its associated morbidity and mortality have led to increased use of non-invasive techniques such as duplex ultrasonography (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). Currently, asymptomatic and symptomatic vertebral artery stenoses are treated by risk factor modification and medical treatment. However, it is recommended that surgical (endarterectomy, reconstruction, and decompression) and endovascular (balloon coronary, bare-metal, and drug-eluting stents) treatments are also used for symptomatic vertebral artery stenosis.

Scoliosis Secondary to Neurofibromatosis Type I Combined With Moyamoya Syndrome: A Case Report

CASE

A 13-year-old girl presenting with scoliosis accompanied by type I neurofibromatosis (NF1) underwent deformity correction surgery. On the second postoperative day, she had sudden-onset acute cerebral infarctions and was diagnosed with moyamoya syndrome. After neurological conservative treatment, at the sixth month after surgery, her symptoms and signs were significantly improved and the daily life was not affected by herself.

CONCLUSION

NF1 scoliosis with moyamoya syndrome is an uncommon inherited disorder. Intracranial vasculopathy is hardly detected from routine preoperative examinations. The specific intracranial vascular examination should be performed for patients with NF1 scoliosis, especially those who have a positive history of cerebral ischemic or hemorrhagic symptoms.

Extracranial Vertebral Artery-Internal Jugular Vein-Spinal Vein Fistula in Neurofibromatosis Type I: Case Report and Literature Review

Background

A cervical arteriovenous fistula (AVF) in neurofibromatosis type I (NF-1) is uncommon, and it brings challenges and difficulty in treatment.

Case Presentation

A 39-year-old woman was diagnosed with an NF-1-associated spontaneous vertebral artery-internal jugular vein-spinal vein fistula. The fistula was placed by coil embolization. Postoperative examination showed that the fistula closure was satisfied, and the patient's abnormal clinical manifestation disappeared without any complications after 24 months of interventional embolization. As per the literature, interventional embolization is currently the main treatment method, and it has the distinguishing features of less trauma, quick recovery, and a good prognosis.

Conclusion

NF-1 associated with a spontaneous arteriovenous fistula is rare in clinical practice, which carries significant challenges in treatment, but can be effectively treated using endovascular embolism. Endovascular embolism could be the potential choice of treatment in NF-1 associated with AVF.

Endovascular Repair for Abdominal Aortic Aneurysm Rupture With Neurofibromatosis Type 1

BACKGROUND

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a rare congenital disorder with an autosomal dominant inheritance. Severe perioperative complications owing to the congenital fragility of the vascular wall in NF1 patients have been reported. The optimal vascular surgical approach remains controversial. We describe endovascular aortic repair of an abdominal aortic aneurysm rupture in a patient with NF1.

CASE PRESENTATION

A 78-year-old woman with NF1 was transferred to our institution with a diagnosis of ruptured abdominal aortic aneurysm. The patient showed multiple café-au-lait spots, numerous neurofibromatosis, and severe scoliosis. Emergency endovascular aortic repair was performed, without technical difficulty. Despite an uneventful postoperative course, she developed an idiopathic left cervical hematoma caused by hemorrhage, and required tracheostomy due to severe airway obstruction. In addition, postoperative CT showed a newly developed saccular aneurysm at the proximal end of the stent graft. On postoperative day 40, she was transferred to a rehabilitation hospital, without recurrent bleeding and saccular aneurysm enlargement.

CONCLUSION

In patients with NF1 who require a vascular surgical procedure, surgeons should consider the vascular wall fragility in selecting the optimal treatment strategy and the possible complications.

RETINAL VASCULAR ABNORMALITIES IN CHILDREN WITH NEUROFIBROMATOSIS TYPE 1

PURPOSE

Retinal vascular abnormalities (RVAs) have been recently described in patients with neurofibromatosis Type 1 (NF1) as vascular tortuosity, best visible on infrared imaging. This study assessed clinical RVA's characteristics in a large series of children with NF1.

METHODS

This retrospective observational study was conducted in children (0-18 years) with an NF1 diagnosis. Using near-infrared imaging, RVAs were classified according to the nature of vessels involvement and their degree of tortuosity.

RESULTS

Retinal imaging from 140 children, with a median age of 8.8 years (1.5-18), was included; 52 patients (37.1%) (81 eyes) exhibited RVAs. These RVAs comprised 96% (50/52) of simple vascular tortuosity and 17% (9/52) of a corkscrew pattern. A corkscrew pattern involved only small veins, whereas simple vascular tortuosity could affect both arteries and veins. No statistically significant age correlation was observed, but evolution of RVAs from simple vascular tortuosity to corkscrew pattern was observed in 5 cases.

CONCLUSION

Retinal vascular abnormalities occurred in 37.1% of children with NF1. These abnormalities may result from NF1 promoting localized tortuosity in both small arteries and veins, whereas only small second-order or tertiary-order venules evolve to a highly tortuous pattern.

Pathophysiology of Vascular Stenosis and Remodeling in Moyamoya Disease

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are progressive vascular pathologies unique to the cerebrovasculature that are important causes of stroke in both children and adults. The natural history of MMD is characterized by primary progressive stenosis of the supraclinoid internal carotid artery, followed by the formation of fragile collateral vascular networks. In MMS, stenosis and collateralization occur in patients with an associated disease or condition. The pathological features of the stenosis associated with MMD include neointimal hyperplasia, disruption of the internal elastic lamina, and medial attenuation, which ultimately lead to progressive decreases in both luminal and external arterial diameter. Several molecular pathways have been implicated in the pathophysiology of stenosis in MMD with functions in cellular proliferation and migration, extracellular matrix remodeling, apoptosis, and vascular inflammation. Importantly, several of these molecular pathways overlap with those known to contribute to diseases of systemic arterial stenosis, such as atherosclerosis and fibromuscular dysplasia (FMD). Despite these possible shared mechanisms of stenosis, the contrast of MMD with other stenotic pathologies highlights the central questions underlying its pathogenesis. These questions include why the stenosis that is associated with MMD occurs in such a specific and limited anatomic location and what process initiates this stenosis. Further investigation of these questions is critical to developing an understanding of MMD that may lead to disease-modifying medical therapies. This review may be of interest to scientists, neurosurgeons, and neurologists involved in both moyamoya research and treatment and provides a review of pathophysiologic processes relevant to diseases of arterial stenosis on a broader scale.

Molecular genetic evaluation of Pediatric Renovascular hypertension due to renal artery stenosis and abdominal aortic Coarctation in Neurofibromatosis type 1

The etiology of renal artery stenosis (RAS) and abdominal aortic coarctation (AAC) causing the midaortic syndrome (MAS), often resulting in renovascular hypertension (RVH), remains ill-defined. Neurofibromatosis type 1 (NF-1) is frequently observed in children with RVH. Consecutive pediatric patients (N = 102) presenting with RVH secondary to RAS with and without concurrent AAC were prospectively enrolled in a clinical data base, and blood, saliva, and operative tissue when available, were collected. Among the 102 children were 13 having a concurrent clinical diagnosis of NF-1 (12.5%). Whole exome sequencing was performed for germline variant detection and RNASeq analysis of NF1, MAPK pathway genes, and MCP1 levels were undertaken in five NF-1 stenotic renal arteries, as well as control renal and mesenteric arteries from children with no known vasculopathy or NF-1. In 11 unrelated children with sequencing data, 11 NF1 genetic variants were identified, of which 10 had not been reported in gnomAD. Histologic analysis of NF-1 RAS specimens consistently revealed intimal thickening, disruption of the internal elastic lamina, and medial thinning. Analysis of transcript expression in arterial lesions documented an approximately 5-fold reduction in NF1 expression, confirming heterozygosity, MAPK pathway activation, and increased MCP1 expression. In summary, NF-1 related RVH in children is rare but often severe and progressive and as such, important to recognize. It is associated with histologic and molecular features consistent with an aggressive adverse vascular remodeling process. Further research is necessary to define the mechanisms underlying these findings.

Rare Neurovascular Diseases in Korea: Classification and Related Genetic Variants

Rare neurovascular diseases (RNVDs) have not been well-recognized in Korea. They involve the central nervous system and greatly affect the patients' lives. However, these diseases are difficult to diagnose and treat due to their rarity and incurability. We established a list of RNVDs by referring to the previous literature and databases worldwide to better understand the diseases and their current management status. We categorized 68 RNVDs based on their pathophysiology and clinical manifestations and estimated the prevalence of each disease in Korea. Recent advances in genetic, molecular, and developmental research have enabled further understanding of these RNVDs. Herein, we review each disease, while considering its classification based on updated pathologic mechanisms, and discuss the management status of RNVD in Korea.

RETINAL VASCULAR ABNORMALITIES RELATED TO NEUROFIBROMATOSIS TYPE 1: Natural History and Classification by Optical Coherence Tomography Angiography in 473 Patients

PURPOSE

To analyze and classify neurofibromatosis Type 1 (NF1)-related retinal vascular abnormalities (RVAs), their natural history and correlation with disease severity, in a large cohort of patients.

METHODS

This was an observational longitudinal study with prospective enrollment. Four hundred and seventy-three patients affected by NF1 and 150 age-matched healthy subjects were consecutively enrolled. Retinal vascular abnormalities were detected by means of near-infrared reflectance and studied by optical coherence tomography angiography. The superficial vascular plexus and the deep vascular complex (DVC) were quantitatively and qualitatively analyzed.

RESULTS

We identified RVAs in 82 of 473 (17%) NF1 patients, but in none of the 150 healthy subjects. A comparison revealed that NF1 patients with RVAs showed a higher number of NF1 diagnostic criteria (4.3 ± 1.5 vs. 3.9 ±1.5, respectively; P = 0.02) than patients without RVAs. Three different RVA types were identified on optical coherence tomography angiography: macrovascular angiomatosis of the sole superficial vascular plexus; macrovascular angiomatosis of the superficial vascular plexus combined with microvascular angiomatosis of the deep vascular complex; and combined macrovascular angiomatosis of both superficial vascular plexus and deep vascular complex. The prospective analysis of optical coherence tomography angiography images showed no significant longitudinal evolution of RVAs (mean follow-up: 3.7 ± 2.8 years). A single patient developed a de novo single RVA, and two RVAs showed detectable changes during follow-up.

CONCLUSION

In NF1 patients, RVAs are a characteristic sign that correlates with a more severe systemic disease expression, usually remaining stable during time. Optical coherence tomography angiography allows for the identification of different RVAs subtypes.

Genetic and Proteomic Contributions to the Pathophysiology of Moyamoya Angiopathy and Related Vascular Diseases

RATIONALE

This literature review describes the pathophysiological mechanisms of the current classes of proteins, cells, genes, and signaling pathways relevant to moyamoya angiopathy (MA), along with future research directions and implementation of current knowledge in clinical practice.

OBJECTIVE

This article is intended for physicians diagnosing, treating, and researching MA.

METHODS AND RESULTS

References were identified using a PubMed/Medline systematic computerized search of the medical literature from January 1, 1957, through August 4, 2020, conducted by the authors, using the key words and various combinations of the key words "moyamoya disease," "moyamoya syndrome," "biomarker," "proteome," "genetics," "stroke," "angiogenesis," "cerebral arteriopathy," "pathophysiology," and "etiology." Relevant articles and supplemental basic science articles published in English were included. Intimal hyperplasia, medial thinning, irregular elastic lamina, and creation of moyamoya vessels are the end pathologies of many distinct molecular and genetic processes. Currently, 8 primary classes of proteins are implicated in the pathophysiology of MA: gene-mutation products, enzymes, growth factors, transcription factors, adhesion molecules, inflammatory/coagulation peptides, immune-related factors, and novel biomarker candidate proteins. We anticipate that this article will need to be updated in 5 years.

CONCLUSION

It is increasingly apparent that MA encompasses a variety of distinct pathophysiologic conditions. Continued research into biomarkers, genetics, and signaling pathways associated with MA will improve and refine our understanding of moyamoya's complex pathophysiology. Future efforts will benefit from multicenter studies, family-based analyses, comparative trials, and close collaboration between the clinical setting and laboratory research.

Neurofibromatosis type 1 with subarachnoid haemorrhage from the left vertebral arteriovenous fistula: case presentation and literature review

We present the case of a 47-year-old woman with neurofibromatosis type 1 (NF1) with subarachnoid haemorrhage (SAH) from the left vertebral arteriovenous fistula, along with a review of previous cases. Our patient had a family history of NF1 and presented to the emergency department with a sudden-onset severe headache and neck pain. CT scan showed SAH. CT angiography revealed a left vertebral arteriovenous fistula and an epidural haematoma. She underwent direct surgery and was discharged without neurologic deficits. To our knowledge, this is the first case of SAH caused by perimedullary drainage of a vertebral arteriovenous fistula associated with NF1. In a literature search, we identified 40 cases of vertebral arteriovenous fistula associated with NF1. The majority of vertebral arteriovenous fistulas occurred on the left side and in women. Patients with vertebral arteriovenous fistula typically experience neck pain, radiculopathy, radiculomyelopathy and bruits.

Rubeosis iridis and macular hemorrhages from multiple Corkscrew retinal vessels in a patient with NF1

PURPOSE

To report a case of a patient with NF1 presenting with ocular findings of AV malformation, multiple retinal hemorrhages, and neovascular glaucoma in the absence of retinal ischemia.

METHODS

Review of the medical record was conducted in accordance with the local IRBt.

RESULTS

A 60-year-old female patient with diagnosis of Neurofibromatosis type1 (NF1) and sudden decrease of vision in her left eye was found to have rubeosis iridis and high intraocular pressure (IOP). On fundus exam multiple corkscrew retinal vessels and retinal hemorrhages were present in her left eye. On Optical Coherence Tomography (OCT) the foveal hemorrhages appeared as outer layer hyperreflective retinal infiltrates whereas in the parafoveal area the hyperreflectivity was present between the RPE and neurosensory retina. Fluorescein Angiogram (FA) showed normal perfusion and no areas of leakage or ischemia. Treatment with anti-angiogenics in a timely manner correlated with a good visual outcome.

CONCLUSIONS

We present a unique patient with NF1, rubeosis iridis, high IOP, and macular hemorrhages from multiple corkscrew retinal vessels in a well perfused retina, who underwent treatment with a single dose of intravitreal Bevacizumab and had an excellent response.

Subclavian Artery Branch Pseudoaneurysm Rupture With Massive Hemothorax in a Patient With Neurofibromatosis Type 1

Neurofibromatosis type 1 is a rare disorder that occurs secondary to pathogenic variants in the NF1 tumor suppressor gene on chromosome 17. Characteristic clinical manifestations include multiple hyperpigmented macules, axillary and inguinal freckling, optic gliomas, and numerous skin neurofibromas. Vasculopathies are a rare complication of this disease and can affect vessels ranging from the proximal aorta to small arterioles, with pathology including arterial stenosis, aneurysms, and arteriovenous malformations. Aneurysms in these patients are often asymptomatic, and most patients with this complication appear for treatment after vessel rupture. We describe a 33-year-old man with neurofibromatosis type 1 who presented with chest pain and was ultimately found to have a ruptured left subclavian artery branch pseudoaneurysm leading to a large hemothorax.

A Case of Duodenal Neuroendocrine Tumor Accompanied by Gastrointestinal Stromal Tumors in Type 1 Neurofibromatosis Complicated by Life-Threatening Vascular Lesions

Patient: Female, 45-year-old

Final Diagnosis: Neuroendocrine tumor

Symptoms: Bleeding

Medication:—

Clinical Procedure: Pancreaticoduodenectomy

Specialty: General and Internal Medicine

Phakomatoses and cutaneous manifestations associated with moyamoya disease and syndrome

Phakomatoses are a group of neurocutaneous disorders whose origin is derived from the embryonic ectoderm. These disorders affect the central nervous system, the eyes, and the skin. This article presents phakomatoses and cutaneous manifestations associated with moyamoya disease and syndrome. Moyamoya disease is a progressive and occlusive disorder of the cerebral vasculature often presenting with particular phakomatoses. This article aims to reveal why patients with phakomatoses qualify for detailed neuroimaging.

A Pilot Study for Investigation of Plasma Amino Acid Profile in Neurofibromatosis Type 1 Patients

BACKGROUND

Neurofibromatosis, also known as Von Recklinghausen disease, is a systemic and progressive genetic disease that primarily affects the skin, eyes, nervous system and bones. The disease can occur in a variety of ways and can vary from individuals. Metabolomic-based research using blood samples has enabled new diagnostic methods to be used in the diagnosis of various diseases, especially cancer. Among metabolites, profiling of plasma free amino acids (PFAA) is a promising approach because PFAAs bind all organ systems and play an important role in metabolism.

OBJECTIVE

This study aimed to determine the characteristics of PFAA profiles in neurofibromatosis patients and the possibility of using them for early detection and treatment of the disease.

METHOD

Patients with a diagnosis of Neurofibromatosis Type I confirmed by genetic analysis and healthy individuals of the same age group without any disease were included in the study. We analysed the nineteen plasma free amino acids (phenylalanine, proline, threonine, arginine, asparagine, cystine, valine, glutamate, tyrosine, serine, glutamine, glycine, tryptophane, leucine, lysine, methionine, isoleucine, aspartate and alanine) from neurofibromatosis Type I patients and control group by liquid chromatography tandem mass spectrometry (LC-MS/MS) in Metabolism Laboratory of Harran University Research and Application Hospital. The results of the plasma free amino acid levels were divided into 3 groups as essential, semi-essential and non-essential. The differences of amino acid levels between groups were determined.

RESULTS

Eight amino acid levels (methionine, arginine, cystine, glutamine, proline, asparagine, serine, aspartate) were significantly altered in patients with neurofibromatosis type 1. In essential amino acids, methionine levels were significantly higher in the patient group than the control group. While the levels of arginine and glutamine in semi-essential amino acids were statistically significantly higher in the patient group, a significant decrease was observed in cystine and proline levels compared to the control group's amino acid levels. In non-essential amino acids group, asparagine, serine and aspartate amino acid levels were significantly higher in the patient group compared to the control group.

CONCLUSION

The current research predicates that eight amino acids, nsmely methionine, arginine, cystine, glutamine, proline, asparagine, serine, aspartate can be considered to be valuable biomarkers for neurofibromatosis type I. This present study is the first to build models for neurofibromatosis Type I screening using plasma free amino acids and the amino acid profile will guide the predicting of the complications that may occur during the course of the disease.

Phenotype and Outcomes of Pulmonary Hypertension Associated with Neurofibromatosis Type 1

Rationale: Pulmonary hypertension (PH) associated with neurofibromatosis type 1 (NF1) is a rare and largely unknown complication of NF1.Objectives: To describe characteristics and outcomes of PH-NF1.Methods: We reported the clinical, functional, radiologic, histologic, and hemodynamic characteristics, response to pulmonary arterial hypertension (PAH)-approved drugs, and transplant-free survival of patients with PH-NF1 from the French PH registry.Measurements and Main Results: We identified 49 PH-NF1 cases, characterized by a female/male ratio of 3.9 and a median (minimum-maximum) age at diagnosis of 62 (18-82) years. At diagnosis, 92% were in New York Heart Association functional class III or IV. The 6-minute-walk distance was 211 (0-460) m. Pulmonary function tests showed low Dl_CO (30% [12-79%]) and severe hypoxemia (Pa_O2 56 [38-99] mm Hg). Right heart catheterization showed severe precapillary PH with a mean pulmonary artery pressure of 45 (10) mm Hg and a pulmonary vascular resistance of 10.7 (4.2) Wood units. High-resolution computed tomography images revealed cysts (76%), ground-glass opacities (73%), emphysema (49%), and reticulations (39%). Forty patients received PAH-approved drugs with a significant improvement in functional class and hemodynamic parameters. Transplant-free survival at 1, 3, and 5 years was 87%, 54%, and 42%, respectively, and four patients were transplanted. Pathologic assessment showed nonspecific interstitial pneumonia and major pulmonary vascular remodeling.Conclusions: PH-NF1 is characterized by a female predominance, a low Dl_CO, and severe functional and hemodynamic impairment. Despite a potential benefit of PAH treatment, prognosis remains poor, and double-lung transplantation is an option for eligible patients.

Congenital abnormalities of the retinal vasculature in neurofibromatosis type I

The aim of this cross-sectional study was to investigate congenital abnormalities of the retinal vasculature (CARVs) in patients with neurofibromatosis type I (NF-1). Forty-eight patients (96 eyes) with NF-1 diagnosed according to the National Institutes of Health (NIH) criteria and 48 healthy controls were included in this study. Standard fundus photographs were obtained for each subject to evaluate the presence and frequency of CARVs. The sensitivity, specificity, and diagnostic accuracy of different cut-off numbers of CARVs were compared with those of the NIH criteria. Forty-four (91.7%) patients in the NF-1 group demonstrated either supranumeraty optic disc vessels or triple branching of the retinal vasculature, and 22 patients (45.8%) demonstrated both findings. The frequencies of these two CARVs were significantly different between the two groups (p < 0.00001). A cut-off value of either one for supranumerary optic disc vessels or triple branching showed the highest accuracy along with sensitivity and specificity of 91.7% and 87.5%. CARVs such as supranumerary optic disc vessels or triple branching were frequently observed in NF-1 patients, and their occurrence was unrelated to the age of patients. Thus, these CARVs could be added as new ophthalmologic manifestions for NF-1 and may potentially enable early diagnosis of NF-1.

Functional and morphological cardiovascular alterations associated with neurofibromatosis 1

Subjects with Neurofibromatosis 1 (NF1) develop vascular complications. The protein product of the gene affected in NF1, neurofibromin, physiologically modulates endothelial function and preserves vascular and myocardial structure. Our study aimed to verify whether subjects with NF1 have early, preclinical abnormalities of carotid artery structure, brachial artery function, and cardiac function. We recruited 22 NF1 subjects without previous cardiovascular events and 22 healthy control subjects. All subjects underwent measurement of carotid artery intima-media thickness (IMT), evaluation of brachial artery endothelial function after ischemia and exercise, and cardiac function. Mean IMT was 543 ± 115 μ in NF1 subjects and 487 ± 70 μ in Controls (p < 0.01). Endothelial function was significantly dumped in NF1 subjects. The dilation after ischemia and exercise was respectively 7.5(± 4.8)% and 6.7(± 3.0)% in NF1 versus 10.5(± 1.2)% and 10.5(± 2.1)% in control subjects (p < 0.02; p < 0.002). Left ventricular systolic function assessed by Global Longitudinal Strain was significantly different between NF1 subjects and Controls: − 19.3(± 1.7)% versus − 21.5(± 2.7)% (p < 0.008). These findings demonstrate that NF1 patients have early morphological and functional abnormalities of peripheral arteries and systolic cardiac impairment and suggest the need for a tight cardiovascular risk evaluation and primary prevention in subjects with NF1.

Orbital malformation with dysplastic infraorbital artery in neurofibromatosis type 1

PURPOSE

To report a case with neurofibromatosis type 1 presenting as prominent enophthalmos and abnormal infraorbital artery.

CASE DESCRIPTION

A 19-year-old man with a family history of neurofibromatosis presented with prominent right enophthalmos. Computed tomography showed orbital dysplasia and enlarged inferior orbital fissure but no plexiform neurofibroma. Prominent intraoperative hemorrhage originated from several abnormal arteries in the infraorbital region during orbital reconstruction. A tortuous and dysplastic infraorbital artery was verified postoperatively by computed tomography angiography. The bleeding vessels were supposed to be the orbital branches of the dysplastic infraorbital artery.

CONCLUSIONS

The orbital malformation and enlargement of inferior orbital fissure probably resulted in an abnormal infraorbital artery. Selective artery embolization may be chosen as a preceding treatment before orbital reconstruction surgery.

An update on the central nervous system manifestations of neurofibromatosis type 1

Neurofibromatosis 1 (NF1) is an autosomal dominant genetic disorder that presents with variable phenotypes as a result of mutations in the neurofibromatosis type 1 (NF1) gene and subsequently, abnormal function of the protein product, neurofibromin. Patients with NF1 are at increased risk for central nervous system (CNS) manifestations including structural, functional, and neoplastic disease. The mechanisms underlying the varied manifestations of NF1 are incompletely understood, but the loss of functional neurofibromin, resulting in sustained activation of the oncoprotein RAS, is responsible for tumorigenesis throughout the body, including the CNS. Much of our understanding of NF1-related CNS manifestations is from a combination of data from animal models and natural history studies of people with NF1 and CNS disease. Data from animal models suggest the importance of both Nf1 mutations and somatic genetic alterations, such as Tp53 loss, for development of neoplasms, as well as the role of the timing of the acquisition of such alterations on the variability of CNS manifestations. A variety of non-neoplastic structural (macrocephaly, hydrocephalus, aqueductal stenosis, and vasculopathy) and functional (epilepsy, impaired cognition, attention deficits, and autism spectrum disorder) abnormalities occur with variable frequency in individuals with NF1. In addition, there is increasing evidence that similar appearing CNS neoplasms in people with and without the NF1 syndrome are due to distinct oncogenic pathways. Gliomas in people with NF1 show alterations in the RAS/MAPK pathway, generally in the absence of BRAF alterations (common to sporadic pilocytic astrocytomas) or IDH or histone H3 mutations (common to diffuse gliomas subsets). A subset of low-grade astrocytomas in these patients remain difficult to classify using standard criteria, and occasionally demonstrate morphologic features resembling subependymal giant cell astrocytomas that afflict patients with tuberous sclerosis complex ("SEGA-like astrocytomas"). There is also emerging evidence that NF1-associated high-grade astrocytomas have frequent co-existing alterations such as ATRX mutations and an alternative lengthening of telomeres (ALT) phenotype responsible for unique biologic properties. Ongoing efforts are seeking to improve diagnostic accuracy for CNS neoplasms in the setting of NF1 versus sporadic tumors. In addition, MEK inhibitors, which act on the RAS/MAPK pathway, continue to be studied as rational targets for the treatment of NF1-associated tumors, including CNS tumors.

Spontaneous evolution of a massive hematoma caused by type 1 neurofibromatosis: Case report

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Vascular complications are the second cause of death in type 1 Neurofibromatosis.

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Spontaneous fistulzation of the hematoma avoided the patient surgical morbidity.

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Venous system involvement is extremely rare in type 1 Neurofibromatosis and surgery should be considered on a case by case basis especially when the risk of iatrogenesis is high.

Introduction

Type1 Neurofibromatosis (NF1) is an autosomal dominant disorder with a great variety of clinical features. Vascular manifestations appear in less than 7%, and venous complications are extremely rare.

Case presentation

We report a case of an enormous cervical hematoma caused by bleeding from the internal jugular vein in a NF1 patient. As the patient refused surgery, natural evolution was marked by spontaneous fistulization and drainage of the mass.

Discussion

Several cases of fragility of both the vessel wall and the surrounding tissue are discussed and two jugular vein aneurysms were reported. Management of such cases remains unclear and some reports describe defective hemostatic control at surgery.

Conclusion

Surgery in NF1 vascular involvement should be considered on a case by case basis especially when the risk of iatrogenesis is high. Surgeons need to be aware of hemorrhagic risks, which could occur because of vessel friability.

A pediatric case of NF1 and moyamoya syndrome: Neuropsychological evaluation pre- and post-EDAS

Studies have shown that a subset of patients with neurofibromatosis type 1 (NF1) experience associated vascular conditions, with moyamoya syndrome one of the most common comorbidities. While NF1 and moyamoya syndrome are each associated with neurocognitive deficits, no neuropsychological data has been presented for an individual with comorbid NF1 and moyamoya syndrome, particularly pre- and post-re-vascularization surgery. The present case describes the neuropsychological profile of a bilingual Latina girl with NF1 and moyamoya syndrome, who was assessed pre- (age 5 years, 9 months) and post-EDAS (age 6 years, 1 month). Each evaluation included a clinical interview and comprehensive battery of neuropsychological tests. Results of pre-EDAS evaluation documented significant deficits in sustained attention, daily executive functioning, and academic abilities, and she met criteria for ADHD-combined type. Results of post-EDAS evaluation revealed generally stable abilities with relative improvements in social, emotional, and behavioral functioning, but relative decline in visuospatial skills, visual spatial learning/memory, and aspects of executive functioning. Math abilities also remained consistently poor and she was diagnosed with a specific learning disability (mathematics). This case study adds to the current literature by being among the first to present pre- and post-surgical neuropsychological data for a child with NF1 and moyamoya syndrome. Findings are discussed in the context of previous literature, the importance of individual socio-cultural considerations in the case (i.e., language, education, culture), and recommendations for future research.

Successful Repair of a Vasculopathic Aneurysmal Brachial Artery in a Patient with Type 1 Neurofibromatosis

Vasculopathy is a well-recognized abnormality associated with neurofibromatosis type 1(NF1) and may cause stenoses, aneurysms, and arteriovenous malformations. We report a challenging case of a woman with NF1, who presented with spontaneous rupture of a brachial aneurysm around her right elbow, on a background of previous debulking and soft tissue reconstructive surgery in the same arm. She underwent successful delayed reconstruction of the brachial artery using an autologous great saphenous vein graft.

Galenic dural arteriovenous fistula in neurofibromatosis type 1 treated with Onyx

Galenic dural arteriovenous fistula (GDAVF) represents a unique, hard-to-treat subgroup of tentorial dural arteriovenous fistulae. Neurofibromatosis type 1 (NF1) has been infrequently associated with different cerebrovascular conditions that may lead to either ischemic or haemorrhagic stroke. Intracranial GDAVF has not been described in NF1 patients. We present an unusual case of GDAVF in a 37-year-old man with NF1. The fistula drained directly to the vein of Galen through multiple feeders. Complete occlusion of the fistula was achieved through trans-arterial embolisation with Onyx (ethylene vinyl alcohol copolymer) in a single treatment session. Deep venous drainage remained intact, and the patient recovered well. To our knowledge, this is the first report on complete closure of GDAVF with NF1 using trans-arterial embolisation. The preservation of functioning of the straight sinus may have contributed to the success of treatment.

Activated androgen receptor accelerates angiogenesis in cutaneous neurofibroma by regulating VEGFA transcription

Accumulating evidence has demonstrated the significant progression of cutaneous neurofibroma (cNF) without necrosis during puberty. However, the molecular events involved in this process remain unclear. The alteration of the steroid hormone levels during puberty has led to the investigation of the expression levels of the androgen receptor (AR). A positive correlation between AR expression and microvessel density has been reported in human cNF tissues in combination with enhanced endothelial cell tube formation in vitro. In addition, activated AR signaling can promote neurofibroma cell growth in vivo and in vitro and tube formation in vitro. In the present study, AR was shown to bind directly to the promoter of vascular endothelial growth factor A (VEGFA), a key factor involved in angiogenesis, and to sequentially induce its expression. Furthermore, the AR inhibitor, MDV3100, downregulated VEGFA expression and abolished endothelial cell recruitment and tube formation. Taken collectively, the findings of this study revealed that AR signaling enhanced tumor growth and angiogenesis in cNF by regulating VEGFA transcription. However, whether AR can be regarded a therapeutic target for cNF requires further investigation.

Retinal microvascular abnormalities in neurofibromatosis type 1

PURPOSE

The aim of this study was to provide a classification of the different retinal vascular arrangements in neurofibromatosis 1 (NF1), with appropriate qualitative and quantitative information.

METHODS

This study was conducted on 334 consecutive patients with NF1 and 106 sex-matched and age-matched healthy control subjects. Each patient underwent a comprehensive ophthalmological examination inclusive of near-infrared reflectance retinography by using the spectral domain Optical coherence tomography (OCT), a complete dermatological examination and 1.5 T MRI scan of the brain to assess the presence of optic nerve gliomas. To evaluate the predictability and the diagnostic accuracy of our identified retinal microvascular arrangements, we calculated the diagnostic indicators for each pattern of pathology, with corresponding 95% CI. In addition, we evaluated the association between the microvascular arrangements and each National Institutes of Health diagnostic criteria.

RESULTS

Microvascular abnormalities were detected in 105 of 334 NF1 patients (31.4%), the simple vascular tortuosity was recognised in 78 of 105 cases (74.3%) and whether the corkscrew pattern and the moyamoya-like type showed a frequency of 42.8% (45 of 105 cases) and 15.2% (16 of 105 cases), respectively. We found a statistically significant correlation between the presence of retinal microvascular abnormalities and the patient age (p=0.02) and between the simple vascular tortuosity, the patient age and the presence of neurofibromas (p=0.002 and p=0.05, respectively).

CONCLUSIONS

We identified microvascular alterations in 31.4% of patients and a statistically significant association with patient age. Moreover, the most frequent type of microvascular alterations, the simple vascular tortuosity, resulted positively associated with age and with the presence of neurofibromas.