The vasculopathy of NF1 and histogenesis control genes

Vertebral arteriovenous fistulae (AVF) and vertebral artery aneurysms in neurofibromatosis type 1: A case report and a systematic review

BACKGROUND

Neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene on the long arm of chromosome 17, which affects the skin, nervous system, eyes, and skeleton system. Vertebral arteriovenous fistula (AVF) associated with neurofibromatosis type I (NF-1) is rare.

CASE PRESENTATION

We report a 31-year-old postpartum woman with NF1 with vertebral arteriovenous fistulae (AVFs). She presented to our hospital because of neck pain, intracranial hypotension headache, and right upper limb weakness. She had a family history of NF1. After endovascular intervention, the AVF disappeared. However, a new aneurysm appeared on the right vertebral artery V5 dissection after 6 months of follow-up.

CONCLUSIONS

The presence of NF1 in patients who present with neurologic signs should prompt further angiography. Awareness of the coexistence between NF1 and AVF or aneurysm is crucial to avoiding diagnostic delays. Endovascular occlusion of VV-AVF in NF-1 patients is effective and safe.

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.

Life-threatening brachial artery hemorrhage and a lethal outcome in patients with neurofibromatosis type 1: two case reports and a review of the literature

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease characterized by neuorocutaneous lesions and multisystem involvement. Other notable features of NF1 include vasculopathy in the form of stenosis, occlusion, aneurysm, pseudoaneurysm, arteriovenous deformity, and rupture, which are difficult to manage and can have fatal outcomes. We describe two cases of extensive and progressive brachial artery hemorrhage following blunt trauma in patients with NF1. Management of these patients included combined endovascular and surgical treatment based on the patients' condition. The patients had a poor prognosis because of uncontrolled bleeding. While one patient died, the other survived, but the involved arm was amputated. Endovascular treatment is a widely used, popular, minimally invasive, and safe method to control the bleeding associated with NF1. However, this treatment can be challenging at times. Close collaboration between an interventional radiologist and surgeon is necessary for optimal treatment and careful follow-up for this condition.

Neurofibromatosis Type 1-Associated Extracranial Vertebral Artery Aneurysm Complicated by Vertebral Arteriovenous Fistula After Rupture: Case Report and Literature Review

BACKGROUND

Extracranial vertebral artery aneurysm related to neurofibromatosis type 1 (NF1) is rare. Aneurysmal rupture typically induces such symptoms as cervical hematoma, hemothorax, and hypotension. Here we report a case of ruptured extracranial vertebral artery aneurysm in a patient with NF1 who, rather than cervical hematoma, hemothorax, or hypotension, developed a vertebral arteriovenous fistula (AVF) after aneurysm rupture.

CASE DESCRIPTION

A 35-year-old woman with a family history of NF1 presented with sudden-onset right neck and shoulder pain. Computed tomography angiography showed a right extracranial vertebral artery aneurysm. She had neither a cervical hematoma nor hypotension; however, angiography showed an AVF secondary to aneurysmal rupture. The patient was treated with endovascular coil embolization to prevent re-rupture. Postoperatively, her right neck and shoulder pain improved, and she was discharged without further neurologic deficits.

CONCLUSIONS

This patient's clinical course suggests that if there is minimal bleeding from an NF1-associated ruptured extracranial vertebral artery aneurysm, then typical symptoms, such as cervical hematoma, hemothorax, and hypotension, may be absent. Thus, ruptured extracranial vertebral artery aneurysm should be considered in the differential diagnosis of patients with NF1 with sudden-onset radiculopathy, even in the absence of typical symptoms. The detection of a vertebral AVF provides a useful clue to the diagnosis of aneurysm rupture in such cases.

Ruptured left external carotid artery aneurysm presenting as upper airway obstruction in von Recklinghausen's disease

•

Vascular abnormalities are recognized but rare manifestations of Neurofibromatosis type 1.

•

Stenoses, aneurysms and pseudoaneurysm are the most common vascular abnormalities.

•

External carotid aneurysm has not been reported before in the litterature.

•

The most common clinical presentation of aneurysms is their spontaneous rupture.

•

Carotid aneurysm rupture can cause a life-threatening upper airway obstruction.

•

Carotid aneurysm in NF-1 can be treated by surgical or endovascular approach or combination of the both.

Introduction

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disorder characterized by café-au-lait macules, neurofibromas, and iris hamartomas. Carotid artery aneurysms rarely affect patients with NF-1 but may be associated with rupture. We report the first episode of a ruptured external carotid aneurysm with severe life-threatening airway obstruction in a NF-1 patient.

Presentation of case

We report a case of NF-1 32-year-old woman admitted to our department for life-threatening upper airway obstruction caused by spontaneous expanding swelling in the left sided neck. The diagnosis of ruptured aneurysm was suspected clinically and confirmed by computed tomography of the neck. The patient required tracheotomy for breathing difficulties and hemostasis was assured surgically by ligation of the external carotid artery.

Discussion

Vascular abnormalities are rare but recognized manifestation of type NF-1. They often affect medium and large sized vessels. Carotid aneurysms are asymptomatic in most patients; they are subject to sudden rupture with potentially devastating consequences. CT angiography is the gold standard for diagnosis of an aneurysmal rupture in NF-1 patients. Treatment consists on surgical ligation, resection and reconstruction or on percutaneous embolization.

Conclusion

Patients with NF-I have a wide spectrum of vascular abnormalities. Particularly, aneurysms can be life-threatening for these patients; their surgical management must be urgent in these situations.

Extracranial internal carotid artery pseudoaneurysm associated with neurofibromatosis type 1 treated with endovascular stenting and coil embolization

An internal carotid artery (ICA) pseudoaneurysm associated with neurofibromatosis type 1 (NF-1) is rare. We report the first case of unruptured extracranial pseudoaneurysm of the ICA in a patient with NF-1 successfully treated with endovascular stenting and coil embolization.A 66-year-old woman diagnosed with NF-1 had sudden left neck pain and massive swelling 3 years earlier. Radiological examination showed a ruptured pseudoaneurysm of the left internal thoracic artery (ITA). The posttreatment computed tomography (CT) scan revealed complete obliteration of the aneurysm of the left ITA and an unruptured pseudoaneurysm of the right ICA. After 3 years of follow-up, a CT scan revealed the enlargement of the pseudoaneurysm of the right extracranial ICA. Endovascular stenting and coil embolization were performed to prevent rupture, and the lesion was completely obliterated. Follow-up angiography at 6 months revealed good flow of the ICA through the stent without any filling of the aneurysm.

The role of CT angiography in the evaluation of pediatric renovascular hypertension

Historically, the evaluation of renovascular hypertension has been accomplished by US, renal scintigraphy and digital subtraction angiography. Based on its high accuracy reported in adults renal CT angiography (CTA) with pediatric-appropriate low radiation dose techniques has become an important tool in the workup of renovascular hypertension in children. Renal CTA has several advantages over more conventional imaging modalities, including rapid and non-invasive acquisition, high resolution and easy reproducibility. Additionally, in our experience high-quality renal CTA can be performed using low-dose radiation exposures and can be acquired without sedation in most instances. This article illustrates by examples the usefulness of renal CTA for diagnosis of childhood renovascular hypertension and provides an overview of renal CTA findings in the most common childhood renovascular diseases.

[Seizures in neurofibromatosis. What is the risk?]

INTRODUCTION

The prevalence and the type of seizures associated with neurofibromatosis 1 (NF1) and 2 (NF2) are not adequately characterized.

STATE OF THE ART

NF1 has a birth incidence of one in 2500, and NF2 one in 25000. Seizures are an occasional complication in NF1 patients and there is no data for NF2 patients. Central nervous system tumors are always suspected, since NF1 and NF2 are caused by mutations in tumor suppressor gene controlling cell proliferation and differentiation.

PERSPECTIVES

The aim of this article is to provide a synthetic overview about epilepsy associated with NF1 and NF2 based on published studies. In NF1, the type of seizures and their response to therapy are reported, the heterogeneity of etiology is also discussed. For NF2 patients, no specific data are available; the current knowledge comes from series of NF2 patients for which seizures has revealed the disease or from isolated case reports of tumors associated with seizures.

CONCLUSION

Cryptogenic epilepsy without anatomic defect is likely to be related to NF1, while seizures seem to be secondary to leptomeningeal tumors (meningioma, meningioangiomatosis) in NF2 patients.

Peripheral arterial ischemic events in cancer patients

Thromboembolic complications are the second leading cause of death in cancer patients. In contrast to the large body of literature on venous thromboembolism (VTE), relatively few reports have focused on the pathogenesis, incidence, management and outcomes of arterial thromboembolic events in patients with malignancy. The purpose of this article is to review the current literature on the etiology, mechanisms, and prognosis of arterial thromboembolic events in cancer patients and outline appropriate screening and management guidelines that may help lower the rates of morbidity and mortality related to these events.

Simulated surgery for a patient with neurofibromatosis type-1 who had severe cervicothoracic kyphoscoliosis and an anomalous vertebral artery

STUDY DESIGN

Case report.

OBJECTIVE

To describe the usefulness of simulated surgery for evaluation of a patient with neurofibromatosis type-1 (NF-1) who had severe cervicothoracic kyphoscoliosis and an anomalous vertebral artery (VA).

SUMMARY OF BACKGROUND DATA

Several surgical procedures have been used in the treatment of cervicothoracic kyphoscoliosis associated with myelopathy in patients with NF-1. However, to our knowledge, there has been no report that describes a surgical procedure for NF-1 patients with anomalous VA at the cervical spine.

METHODS

A 45-year-old man with NF-1 developed cervical myelopathy. Preoperative examinations revealed severe cervicothoracic kyphoscoliosis, dystrophic changes of the cervical vertebrae, and the anomalous course of a VA and VA aneurysms. To assist in the preoperative planning and intraoperative navigation, we created 3-dimensional (3D) full-scale models of the patient's spine. Using a model, we performed a simulation of the planned surgery for spinal cord decompression with spinal fusion through both anterior and posterior approaches.

RESULTS

Through the simulation, we could evaluate the risk of VA injury at the process of corpectomy, and altered the surgical procedure for the spinal cord decompression with spinal fusion from a posterior approach and a bone graft alone from an anterior approach. We accomplished the surgery successfully without any neurovascular complications. After surgery, the patient experienced relief from myelopathy.

CONCLUSION

Preoperative surgical simulation using a 3D full-scale model was useful for improving the accuracy and safety of the surgery for cervicothoracic kyphoscoliosis with NF-1.

Neurofibromatosis type 1 is a disorder of dysplasia: the importance of distinguishing features, consequences, and complications

BACKGROUND

The disorder neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene, which influences the availability of activated Ras and the latter's control of cellular proliferation. Emphasis on this aspect of NF1 has focused attention on the tumor suppression function of NF1 and thereby displaced attention from the gene's role in initial normal tissue formation, maintenance, and repair.

METHODS

Clinical and neuroimaging data systematically compiled over more than 30 years are analyzed to document the involvement of multiple organs and tissues, often with an embryonic origin. In addition, recent literature based on selective knockout mouse experiments is cited to corroborate embryonic dysplasia as an element of NF1 pathogenesis.

RESULTS

Tissue dysplasia, both ab initio and as part of tissue maintenance and wound healing, is a key clinical and pathogenetic aspect of NF1 and thereby provides a rationale for differentiating the elements of NF1 into features, consequences, and complications.

CONCLUSIONS

NF1 is a histogenesis control gene that also has properties that overlap with those of a tumor suppressor gene. Both its neoplastic and dysplastic manifestations become more amenable to understanding and treatment if they are differentiated at three levels--specifically, features, consequences and complications.

Ruptured subclavian artery pseudo-aneurysm associated with Neurofibromatosis type 1

OBJECTIVE

A subclavian artery aneurysm associated with Neurofibromatosis type 1 (NF 1) is extremely rare. We report a ruptured pseudo-aneurysm of the subclavian artery in a patient with NF 1 treated with endovascular surgery.

CLINICAL DESCRIPTION

A 51 year old man with NF 1 presented with initially sudden left neck pain and continuous dysphagia. Radiological examination showed a pseudo-aneurysm of the left subclavian artery. Endovascular stenting and coil embolisation was performed to prevent rebleeding and the lesion was completely obliterated. Follow-up angiography at 3 months revealed good flow through the stent without flow into the pseudo-aneurysm.

CONCLUSION

Our patient is the first reported example of successful endovascular treatment for a ruptured subclavian artery pseudo-aneurysm associated with NF 1. Endovascular stenting and coil embolisation for the ruptured subclavian artery pseudo-aneurysm was very effective.

Extracranial vertebral artery involvement in neurofibromatosis type I. Report of four cases and literature review

SUMMARY

Neurofibromatosis type 1 (NF-1) is one of the most common inherited diseases and as an autosomal dominant genetic disorder results from NF-1 gene mutation with 100% penetration and wide phenotypic variability. The disease can involve a wide variety of tissues derived from all three embryonic layers. NF-1 vasculopathy has been described primarily in peripheral arteries, but arteries supplying the CNS may also be involved. Of those, extracranial vertebral involvement is the commonest and most important. A series of four patients with NF-1 and vascular disease of the vertebral artery is described with a review of the pathophysiology, vascular phenotypes, their management and the pertinent literature.

PSEUDOTUMORAL PRESENTATION OF A CERVICAL EXTRACRANIAL VERTEBRAL ARTERY ANEURYSM IN NEUROFIBROMATOSIS TYPE 1

OBJECTIVE

Neurofibromatosis Type 1 (NF1) is known to be associated with vascular lesions. Association with an extracranial vertebral artery aneurysm is very rare. We report the case of such an aneurysm mimicking a cervical neurofibroma in NF1.

CLINICAL PRESENTATION

An 18-year-old woman with previously diagnosed NF1 presented with a C6 radiculopathy. There were no clinical features suggesting a vascular origin for the lesion. The computed tomographic and standard magnetic resonance imaging scans showed a C5–C6 contrast-enhancing lesion responsible for bony erosion. Subsequent, magnetic resonance angiography and digital subtraction angiography diagnosed the lesion as a C5–C6 vertebral artery aneurysm.

INTERVENTION

The lesion was treated by endovascular occlusion of both the aneurysm and the parent vertebral artery with an initial immediate disappearance of the pain.

CONCLUSION

This case serves as a reminder of the importance of ruling out a vertebral artery aneurysm with angiography when managing cervical lesions in patients with NF1.

Neurofibromin: a general outlook

Neurofibromin is a cytoplasmic protein that is predominantly expressed in neurons, Schwann cells, oligodendrocytes, astrocytes and leukocytes. It is encoded by the gene NF1, located on chromosome 17, at q11.2, and has different biochemical functions, including association to microtubules and participation in several signaling pathways. Alterations in this protein are responsible for a phacomatosis named neurofibromatosis type 1.

[Imaging features of neurofibromatosis type 1]

Neurofibromatosis type 1 (NF1) is the most common of all the phakomatoses. It is an autosomal dominant disorder, with about 50% of patients being new mutations. NF1 is diagnosed based on the presence of well established diagnostic criteria. Prominent cutaneous manifestations include cafe-au-lait spots, freckling and cutaneous neurofibromas. CNS lesions are frequent and imaging is valuable for diagnosis, treatment and follow-up of patients. Tumors of the central nervous system are frequent. Optic nerve glioma usually affects younger patients with clinical symptoms in one third of cases. MRI shows fusiform enlargement with variable enhancement of the optic nerve. These tumors are usually non-aggressive with good prognosis. Other gliomas and astrocytomas can occur as well, usually midline in location, that also generally have good prognosis. Non-tumoral white matter lesions, referred as unidentified bright objects or UBO's, are frequently observed, typically in the basal ganglia and posterior fossa structures. These lesions are usually seen during childhood and they typically diminish with age. The distinction between UBO's and other tumors may be difficult to achieve at imaging, and a malignant evolution may very rarely be observed. Patients with NF1 may have hydrocephalus and dural sac anomalies leading to meningocele formation. Neurofibromas and plexiform neurofibromas involve peripheral nerves and nerve sheaths. Plexiform neurofibromas may cause radicular symptoms. They more frequently involve the lumbosacral plexus. Neurofibromas are homogeneous oval shaped tumors that may extend into the spinal canal. Neurofibrosarcoma is the main cause of death of NF1 patients less than 40 years of age. It may develop de novo or from sarcomatous degeneration of a pre-existing plexiform neurofibroma. It should be suspected in patients with new onset of symptoms or patients with changing symptoms. At imaging, it is characterized by a large heterogeneous tumor invading adjacent structures. Osseous lesions have been described including progressive thoracic scoliosis, vertebral anomalies (posterior scalloping is very suggestive), long bones anomalies with frequent bowing of the tibia, sometimes resulting in pseudarthrosis, and rib anomalies with ribbon ribs. Vascular lesions may occur resulting in arterial hypertension and aneurysm formation.