Vasculopathies of Neurofibromatosis Type 1 (von Recklinghausen Disease)

Potential Fatal Complication of Neurofibromatosis Type 1: Acute Upper Airway Obstruction Due to Ruptured Transverse Cervical Artery Aneurysm

Neurofibromatosis type 1 (NF1) can cause vascular complications even in undiagnosed NF1 patients. A ruptured aneurysm of the branches of the subclavian artery is a rare but life-threatening event, and the hemorrhage can cause upper airway obstruction. We present a case of NF1 patient with a ruptured transverse cervical artery aneurysm, which led to a nearly obstructed airway. A 52-year-old man who was not previously diagnosed with NF1 presented with sudden pain from the left shoulder to the neck. Since childhood, he has had multiple cutaneous neurofibromas and café-au-lait macules, and freckling in the bilateral axillae. His swollen left side of the neck and left shoulder suggested a hematoma, which compressed the upper airway. Contrast-enhanced computed tomography revealed a cervical hematoma caused by a ruptured aneurysm of the transverse cervical artery. We performed awake fiberoptic intubation because a difficult airway was predicted and surgical airway management may have been impossible due to the anterior cervical hematoma. His airway was secured, and his aneurysm was successfully treated by coil embolization. Based on his cutaneous findings, he was finally diagnosed with NF1. Those who have café-au-lait macules and cutaneous neurofibromas may present with acute cervical hematoma, and it is important to consider the possibility of ruptured aneurysms in the neck region. When patients develop an acute cervical hematoma that causes an acute upper airway obstruction, emergency physicians should consider awake fiberoptic intubation to secure the airway.

HISTOLOGIC AND MORPHOLOGIC CHARACTER OF PEDIATRIC ABDOMINAL AORTIC DEVELOPMENTAL COARCTATION AND HYPOPLASIA

OBJECTIVES

Abdominal aortic coarctation and hypoplasia are uncommon diseases, recognized most often in pediatric-aged individuals. Comprehensive studies regarding the pathologic spectrum of these aortopathies are nonexistent. This investigation was undertaken to better define the histologic and morphologic character of abdominal aortic narrowings affecting children and assess its potential relevance to contemporary clinical practice.

METHODS

Aortic specimens obtained during open operations in children being treated for symptomatic, noninflammatory abdominal aortic narrowings at the University of Michigan were subjected to histologic study following hematoxylin-eosin, Movat, Verhoeff Van Gieson, and Masson's trichrome preparations. Microscopic findings were correlated with the anatomic aortic images. In addition, a detailed review was completed of all prior reports in the English literature that included images depicting the histologic character of noninflammatory abdominal aortic narrowings in children.

RESULTS

Among a series of 67 pediatric-aged individuals undergoing open surgical interventions for abdominal aortic narrowings, eight children ranging in age from 9 months to 18 years, had adequate aortic tissue available for study. The loci of the specimens paralleled the anatomic sites of segmental coarctations observed in the entire series, with involvement of the suprarenal abdominal aorta (3), intrarenal aorta (2), and infrarenal aorta (1). Diffusely hypoplastic abdominal aortas (2) included one case of a de facto aortic duplication, represented by a channel that paralleled the narrow native aorta and gave origin to celiac artery branches, as well as the superior mesenteric and renal arteries. Concentric or eccentric intimal fibroplasia was observed in every aorta, often with internal elastic fragmentation and duplication (4). Media abnormalities included elastic tissue disorganization (3), and focal medial fibrosis (1). Organizing luminal thrombus occurred in two infants. Coexistent ostial stenoses of the celiac, superior mesenteric, or renal arteries were observed in all but the only child who having an infrarenal aortic coarctation. Neurofibromatosis-1 affected one child whose histologic findings were indistinguishable from those of the other children. Review of prior published histologic images of abdominal aortic coarctation and hypoplasia affecting children from other centers revealed a total of 14 separate reports, each limited to single case photomicrographs of which 11 exhibited intimal fibroplasia.

CONCLUSIONS

Intimal fibroplasia is a common accompaniment of developmental abdominal aortic coarctation and hypoplasia. It is posited that intimal fibroplasia, that is likely progressive in instances of abnormal shear stresses in these diminutive vessels, may contribute to less salutary outcomes following endovascular and certain open reconstructions of pediatric abdominal aortic narrowings.

Characterization of Two Loss-of-Function NF1 Variants in Chinese Patients and Potential Molecular Interpretations of Phenotypes

Neurofibromatosis type 1 (NF1) is a common genetic disorder characterized by cafe'-au-lait spots, skinfold freckles, the formation of neurofibromas, skeletal dysplasia, vascular dysplasia, and an increased risk of malignant tumors. In this study, two Chinese NF1 children troubled with bone lesions or hypertension were reported. A de novo NF1 mutation (c.4925T > A/p.V1642E) and a maternally inherited NF1 mutation (c.4883T > A/p.L1628∗) were identified by molecular sequence. According to the ACMG/AMP guidelines, the c.4925T > A was classified as variants of uncertain significance (VOUS) while the c.4883T > A mutation was identified as likely Pathogenic. Further study found that these two NF1 mutants had lost their function to inhibit the Ras/Erk signaling and the proliferation of cells, which could interpretate some phenotypes of these two NF1 patients. We also observed these two NF1 mutants displayed decreased protein stability with increased ubiquitination levels compared with that of wild-type NF1.

Hypertension in Children and Adolescents with Turner Syndrome (TS), Neurofibromatosis 1 (NF1), and Williams Syndrome (WS)

PURPOSE OF REVIEW

Turner syndrome (TS), neurofibromatosis type 1(NF1), and William Syndrome (WS) are 3 genetic conditions that are all associated with a substantial increase in risk of hypertension. In this review, we focus on factors leading to hypertension and on clinical manifestations and management of hypertension in children and adolescents with these genetic conditions RECENT FINDINGS: In most instances, hypertension is secondary. There is a high prevalence of masked hypertension in TS; however, the extent to which control of the BP helps reduce the risk of aortic dissection/aneurysm in TS is not yet fully elucidated. Vasculopathies are the least emphasized but most important manifestation of NF1. Of note, routine screening for pheochromocytoma in NFI is not recommended as it is not cost-effective. Cardiovascular complications are the major cause of death in patients with WBS. ABPM identifies patients without overt aortic or renovascular narrowing. Antihypertensive agents such as ARBs that have direct vascular wall effects and agents that inhibit oxidative stress (minoxidil) should be considered, even in those who do not exhibit overt hypertension. Elevated blood pressure in children and adolescence manifests early with end-organ changes and when left untreated, increases risk for premature onset of cardiovascular disease. Vigilant monitoring of the blood pressure is recommended. Accurate early diagnosis and management of hypertension will delay or prevent target organ damage and ensure a healthier transition to adulthood among children afflicted with these conditions.

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

Renovascular hypertension in children

Paediatric hypertension, defined as systolic blood pressure > 95th percentile for age, sex and height is often incidentally diagnosed. Renovascular hypertension (RVH) is responsible for 5-25% of hypertension in children. Renal artery stenosis and middle aortic syndrome can both can be associated with various conditions such as fibromuscular dysplasia, Williams syndrome & Neurofibromatosis type 1. This paper discusses the approaches to diagnosis and interventional management and outcomes of renovascular hypertension in children. Angiography is considered the gold standard in establishing the diagnosis of renovascular disease in children. Angioplasty is beneficial in the majority of patients and generally repeated angioplasty is considered more appropriate than stenting. Surgical options should first be considered before placing a stent unless there is an emergent requirement. Given the established safety and success of endovascular intervention, at most institutions it remains the preferred treatment option.

Myocardial Infarction in a 28-Year-Old Male With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder that affects multiple systems throughout the body. Although there are multiple documented vasculopathies that can be seen in NF1, there are very few documented cases of coronary artery aneurysms with complete thrombosis of the ectatic vessel resulting in myocardial infarction. This case report describes a 28-year-old male with a past medical history of NF1 who presented with an anterolateral ST-segment elevation myocardial infarction. He underwent urgent cardiac catheterization, which was significant for severe thrombotic occlusion of the mid-left anterior descending artery (LAD) with thrombolysis in myocardial infarction (TIMI) flow 0. The LAD was noted to be severely ectatic. Percutaneous coronary intervention (PCI) with thrombectomy was attempted and was unsuccessful, with TIMI flow 0 after the intervention attempt. An echocardiogram was performed, which showed left ventricular ejection fraction (LVEF) of 30%-35%. This case report is presented to familiarize physicians with the rare vasculopathies that can occur in patients with NF1. Occlusive or aneurysmal disease can occur almost anywhere in the body in patients with NF1 due to the proliferation of fusiform endothelial cells in the blood vessels.

Histologic and morphologic character of pediatric renal artery occlusive disease

OBJECTIVE

The pathologic nature of pediatric renal artery occlusive lesions causing renovascular hypertension has been the subject of numerous anecdotal reports. This study was undertaken to define the character of childhood renal artery stenoses. A better understanding of this disease is particularly germane, given its unknown etiology and the limited success of certain contemporary treatment options.

METHODS

Renal artery specimens obtained during open operations in children being treated for renovascular hypertension from 2004 to 2016 were studied. Excluded from study were arteries subjected to earlier open or endovascular operations. Histologic preparations employing hematoxylin-eosin, Movat, Masson trichrome, and Verhoeff-van Gieson stains allowed characterization of the intima, media, and adventitial tissues. External and luminal diameters were measured. Microscopic data were correlated with preoperative arteriographic images. The histologic and morphologic findings were assessed in regard to coexistent nonrenal arterial and aortic lesions as well as known syndromic diseases.

RESULTS

Thirty-three stenotic renal arteries from 28 children were subjected to examination. Stenoses involved the proximal-ostial renal arteries (24), central renal arteries (7), and distal segmental renal arteries (2). Ostial stenoses commonly exhibited preocclusive concentric hyperplasia of intimal tissues, frequent internal elastic lamina disruptions, and diminutive and discontinuous media. Central and distal renal stenoses most often exhibited lesser intimal cellular hyperplasia and more noticeable fibrodysplasia of the media and adventitia. The mean external and luminal diameters of the renal arteries having ostial stenoses were smaller than the expected renal artery size for a given age. Abdominal aortic coarctation or hypoplastic aortas occurred in 14 children. Neurofibromatosis type 1 affected four children with ostial renal artery disease and one child with midrenal artery disease, but there were no distinguishing features unique to their stenoses.

CONCLUSIONS

Pediatric renal artery stenotic disease affects exceedingly small arteries. Ostial lesions frequently exhibit extensive luminal encroachments characterized by cellular hyperplasia of intimal tissues and scant medial smooth muscle. Central and distal renal arterial stenoses were characterized most often by extensive fibrodysplasia of the media and adventitia. The early success and durability of catheter-based angioplasty may be compromised by the cellular abnormalities of pediatric renal artery occlusive disease observed in this investigation.

Diagnosis of neurofibromatosis type 1 after rupture of aneurysm and consequent fatal hemothorax

Patients with neurofibromatosis type 1 (NF1) can develop both benign and malignant tumors throughout their lives. A 49-year-old man was transferred to the emergency department with complaints of sudden right dorsal pain and respiratory discomfort. He was in shock on arrival. On finding significantly decreased permeability of the left lung field in chest X-ray, drainage was immediately performed. Subsequent computed tomography (CT; Lammert et al., 2005) angiography revealed the extravasation of contrast media from the deep carotid artery, a branch of subclavian artery. It suggested rupture of an aneurysm located at a rare site; the ruptured aneurysm penetrated the pleura, causing shock. The patient was resuscitated. Transcatheter arterial embolization (TAE; Evans et al., 2010) was successfully performed. Immediate drainage, resuscitation, and TAE 2 improved his condition. Most NF1 patients have café-au-lait macules; café-au-lait macules tend to fade with age. Importantly, café-au-lait macules, neurofibromas, and Lisch nodules were noticed at admission. NF1 patients are likely to have a malignant neoplasm when they are young. The patient had been diagnosed with thyroid cancer when he was young. As his deceased mother was an NF1 patient, we diagnosed him with NF1. Detailed patient history and early-stage examination led to the early diagnosis. NF1 should be considered as an early differential diagnosis to improve the outcome of patients in such cases.

Left colic artery aneurysm rupture after stent placement for abdominal aortic aneurysm associated with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease of the skin and soft tissue. Aneurysms associated with NF1 can occur, but a secondary aneurysm rupture is very rare, with very few cases reported in literature.

CASE PRESENTATION

We describe the case of a 67-year-old female with NF1 who underwent endovascular aneurysm repair (EVAR) for an abdominal aortic aneurysm (AAA) rupture. She developed a type Ib endoleak requiring a redo-EVAR. Eighteen days after her primary operation, she was found to have two new left colic artery aneurysms. She required emergency surgery consisting of a left hemicolectomy and transverse colon colostomy. Pathology showed neurofibromatous changes to the peri-vasculature tissue, consistent with her underlying disease.

CONCLUSIONS

Although rare, secondary aneurysms can occur following AAA repair. Patients with soft tissue connective tissue disorders, like NF1, may be at an increased risk for development of these secondary aneurysms. Endovascular repair appears to be a safe approach for NF1 patients with AAA, but endovascular management can be challenging in the setting of NF1. Surgeons should be ready to convert to open surgery if the patient displays persistent signs of bleeding or structural changes related to connective tissue disorders like NF1.

Whole-exome sequencing of duodenal neuroendocrine tumors in patients with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a hereditary cancer predisposition syndrome characterized by frequent cutaneous and nervous system abnormalities. Patients with NF1 also have an increased prevalence of multiple gastrointestinal and peripancreatic neoplasms-neuroendocrine tumors of the ampulla that express somatostatin are particularly characteristic of NF1. In this study, we characterize the genetic alterations of a clinically well-characterized cohort of six NF1-associated duodenal neuroendocrine tumors using whole-exome sequencing. We identified inactivating somatic mutations in the NF1 gene in three of six tumors; the only other gene altered in more than one tumor was IFNB1. Copy number analysis revealed deletion/loss of heterozygosity of chromosome 22 in three of six patients. Analysis of germline variants revealed germline deleterious NF1 variants in four of six patients, as well as deleterious variants in other tumor suppressor genes in two of four patients with deleterious NF1 variants. Taken together, these data confirm the importance of somatic inactivation of the wild-type NF1 allele in the formation of NF1-associated duodenal neuroendocrine tumors and suggest that loss of chromosome 22 is important in at least a subset of cases. However, we did not identify any genes altered in the majority of NF1-associated duodenal neuroendocrine tumors that uniquely characterize the genomic landscape of this tumor. Still, the genetic alterations in these tumors are distinct from sporadic neuroendocrine tumors occurring at these sites, highlighting that unique genetic alterations drive syndromic tumors.

Pulmonary hypertension associated with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a frequent autosomal dominant genetic disorder with a prevalence of 1 in 3000. Pulmonary hypertension (PH) associated with NF1 (PH-NF1) is a rare but severe complication of NF1 and is classified as Group 5 PH, defined as “PH with unclear and/or multifactorial mechanisms”. A literature review in PubMed on the association between NF1 and PH identified 18 articles describing 31 cases. PH-NF1 was characterised by a female predominance, an advanced age at diagnosis, an association with parenchymal lung disease in two out of three cases and poor long-term prognosis. NF1 is generally associated with interstitial lung disease but some cases of severe PH without parenchymal lung disease suggest that there could be a specific pulmonary vascular disease. There is no data available on the efficacy of specific pulmonary arterial hypertension treatment in PH-NF1. Therefore, these patients should be evaluated in expert PH centres and referred for lung transplantation at an early stage. As these patients have an increased risk of malignancy, careful assessment of the post-transplant malignancy risk prior to listing for transplantation is necessary. Clinical trials are needed to evaluate promising treatments targeting the RAS-downstream signalling pathways.

Pulmonary hypertension is a rare but severe complication of neurofibromatosis type 1. There are no data about the efficacy of specific PAH treatment in this disease and lung transplantation should be discussed at an early stage.http://ow.ly/JMU030lezfY

Severe dyspnea in a patient with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a genetic disease in which pulmonary complications are rare, but severe, especially pulmonary hypertension (PH). The mechanisms underlying the onset of PH in patients with NF1 are unclear and might be multifactorial. In particular, the frequent presence of pulmonary parenchymal lesions makes etiological diagnosis of PH difficult. We describe here the case of a patient with NF1 admitted to our clinic with dyspnea and right heart failure revealing severe pre-capillary PH. Parenchymal lesions were mild and PH was attributed to pulmonary vascular involvement. Clinical and hemodynamic conditions of the patient improved under pulmonary arterial hypertension-specific combination therapy. This case suggests that treatment of PH due to pulmonary vascular involvement in NF1 may be aligned with recommendations for PAH treatment.

Nf1+/- monocytes/macrophages induce neointima formation via CCR2 activation

Persons with neurofibromatosis type 1 (NF1) have a predisposition for premature and severe arterial stenosis. Mutations in the NF1 gene result in decreased expression of neurofibromin, a negative regulator of p21(Ras), and increases Ras signaling. Heterozygous Nf1 (Nf1(+/-)) mice develop a marked arterial stenosis characterized by proliferating smooth muscle cells (SMCs) and a predominance of infiltrating macrophages, which closely resembles arterial lesions from NF1 patients. Interestingly, lineage-restricted inactivation of a single Nf1 allele in monocytes/macrophages is sufficient to recapitulate the phenotype observed in Nf1(+/-) mice and to mobilize proinflammatory CCR2+ monocytes into the peripheral blood. Therefore, we hypothesized that CCR2 receptor activation by its primary ligand monocyte chemotactic protein-1 (MCP-1) is critical for monocyte infiltration into the arterial wall and neointima formation in Nf1(+/-) mice. MCP-1 induces a dose-responsive increase in Nf1(+/-) macrophage migration and proliferation that corresponds with activation of multiple Ras kinases. In addition, Nf1(+/-) SMCs, which express CCR2, demonstrate an enhanced proliferative response to MCP-1 when compared with WT SMCs. To interrogate the role of CCR2 activation on Nf1(+/-) neointima formation, we induced neointima formation by carotid artery ligation in Nf1(+/-) and WT mice with genetic deletion of either MCP1 or CCR2. Loss of MCP-1 or CCR2 expression effectively inhibited Nf1(+/-) neointima formation and reduced macrophage content in the arterial wall. Finally, administration of a CCR2 antagonist significantly reduced Nf1(+/-) neointima formation. These studies identify MCP-1 as a potent chemokine for Nf1(+/-) monocytes/macrophages and CCR2 as a viable therapeutic target for NF1 arterial stenosis.

Neurofibromatosis type 1 complicated by atypical coarctation of the thoracic aorta

Neurofibromatosis type 1 (NF1) is a relatively common autosomal dominant genetic disorder with a prevalence of 1 in 3,000 (0.03%) at birth. Clinical features are café-au-lait macules, intertriginous freckling, dermal neurofibroma, iris hamartoma (Lisch nodules), and learning disability. NF1 vasculopathy is a serious but underrecognized complication involving the cerebrovascular and cardiovascular systems. The incidence of hypertension in patients with NF1 is around 1% and is associated mainly with renal artery stenosis in children. Only a few cases of thoracic aortic coarctation in association with hypertension and neurofibromatosis have been reported. Here we describe the case of a 4-year-old girl who presented with NF1 and hypertension due to atypical coarctation of the thoracic aorta. The diagnosis of coarctation of the thoracic aorta at the Th5-to-Th6 level was made following catheterization with a pressure gradient of 40 mmHg. The patient underwent surgery comprising resection of the coarctation of the thoracic aorta and graft interposition. On the basis of our findings, annual assessment of blood pressure is advised for patients with NF1.

Pulmonary hypertension in patients with neurofibromatosis type I

Neurofibromatosis type I (NF1) is a rare genetic disease caused by mutations in the NF1 gene, which codes for tumor suppressor neurofibromin. NF1 is transmitted as an autosomal dominant and fully penetrant trait with no sex predominance. Precapillary pulmonary hypertension (PH) is a severe complication of NF1, initially described in patients with advanced parenchymal lung disease, which may complicate the course of NF1. We conducted this study to describe clinical, functional, radiologic, and hemodynamic characteristics and outcome of patients with NF1-associated PH. We identified 8 new cases of NF1-associated PH in patients carrying a NF1 gene mutation. No bone morphogenic protein receptor 2 (BMPR2) point mutation or large size rearrangements were identified. Seven female patients and 1 male patient were reported, suggesting a possible female predominance. PH occurred late in the course of the disease (median age, 62 yr; range, 53-68 yr). Dyspnea and signs of right heart failure were the major symptoms leading to the diagnosis of PH. At diagnosis, patients had severe hemodynamic impairment with low cardiac index (median, 2.3 L/min per m2; range, 1.9-4.7) and elevated indexed pulmonary vascular resistance (median, 15.1 mm Hg/L/min per m2; range, 4.5-25.9). All patients were in New York Heart Association functional class III with severe exercise limitation (median 6-min walk distance, 180 m; range, 60-375 m). Most patients had associated parenchymal lung disease, but some had no or mild lung involvement with disproportionate pulmonary vascular disease. Overall, the impact of PH therapy was limited and outcomes were poor. In conclusion, PH represents a rare but severe complication of NF1, characterized by female predominance, late onset in the course of NF1, and severe functional and hemodynamic impairment. Because of poor outcome and limited impact of specific PH therapy, eligible patients require early referral for lung transplantation. Further studies are needed to better understand the pathophysiology and the role, if any, of neurofibromin in NF1-associated PH.

[Involvement of peripheral arteries in Von Recklinghausen neurofibromatosis]

Arterial lesions are relatively rare in neurofibromatosis type I but can have potentially serious consequences for the patient. We report two clinical cases of peripheral arterial involvement in neurofibromatosis type 1. The first case was a 25-year-old female with Von Recklinghausen disease who developed a swollen tender mass around her left arm. The arterial CT scan revealed a false aneurysm of the brachial artery. The surgical procedure involved repair of the false aneurysm, and ligation of the brachial artery. Intra- and postoperative bleeding was severe, leading to hemodynamic instability and impaired hemostasis. The patient died on day 2, postoperatively. The second case involved a 17-year-old male with Von Recklinghausen disease who presented stage II arteritis of the right lower limb. Arteriography revealed a long stenosis of the right superficial femoral artery extending to the popliteal artery and an important collateral circulation in the leg arteries. Medical treatment with regular clinical supervision was recommended in this patient.

Portal venous system aneurysms: imaging, clinical findings, and a possible new etiologic factor

OBJECTIVE

The aims of this study were to present the prevalence, imaging and clinical findings, and possible causes of portal venous system aneurysms.

MATERIALS AND METHODS

From 1998 to 2006, a total of 38 portal venous system aneurysms identified in 25 patients were retrospectively reviewed. The data of seven patients diagnosed using color Doppler sonography or CT before March 2004 were not consecutive, but the data recorded thereafter comprised the analysis of 4,186 consecutive patients who underwent routine abdominal MDCT. The patients were 14 men and 11 women (mean age -/+ SD, 53 -/+ 17 years).

RESULTS

The prevalence of portal venous system aneurysm among 4,186 consecutive patients was 0.43%. There were no differences with respect to patient age, patient sex, and intrahepatic or extrahepatic location of aneurysm between those with and those without portal venous system aneurysm. Seven of the 25 patients with portal venous system aneurysm were symptomatic because of portal vein thrombosis, and six of them had recurrence. These patients had significantly larger aneurysms than those without symptoms. Four of those seven symptomatic patients evaluated for thrombophilia had an underlying defect. Other associated findings were splenomegaly (n = 16), portal hypertension (n = 8), cirrhosis (n = 3), psoriasis (n = 2), portal vein variation (n = 1), chronic pancreatitis (n = 1), and cutis laxa (n =1).

CONCLUSION

Portal venous system aneurysms were rare in our study group but occurred more frequently than previously thought. All thrombosed aneurysms, most with a recurrence, were symptomatic and larger in patients with symptoms of portal venous system aneurysm than in those without symptoms. There were no differences among patients with portal venous system aneurysm and those without portal venous system aneurysm with respect to patient age and patient sex. Among those with aneurysms, there was no difference between subjects with intrahepatic versus extrahepatic aneurysms. A thrombophilic defect probably played a role in development of thrombosis in the portal venous system aneurysm.

Ruptured femoropopliteal artery aneurysms in von Recklinghausen neurofibromatosis

A 38-year-old woman with neurofibromatosis type 1 was referred for massive swelling of the left thigh, pain, and anemia. Angiography demonstrated three saccular aneurysms of the femoropopliteal artery. The largest measured 3 cm in diameter. Resection of the aneurysms and femoropopliteal interposition grafting using reversed saphenous vein was performed through a medial surgical approach. Arterial involvement in neurofibromatosis is a well known but infrequent occurrence. Stenotic lesions predominate. Aneurysmal defects are less common, and rupture of peripheral arteries is exceptional. Neurofibromatous invasion and dysplasia of the tunica media of the femoropopliteal vessel were confirmed by means of pathologic study. We think this is the second reported case of a femoropopliteal artery aneurysm and rupture associated with neurofibromatosis.

Is Pulmonary Arterial Hypertension in Neurofibromatosis Type 1 Secondary to a Plexogenic Arteriopathy?

BACKGROUND

Neurofibromatosis type 1 (NF1) is a common disorder of dysregulated tissue growth secondary to mutations in the tumor suppressor gene NF1. Pulmonary arterial hypertension (PAH) in patients with NF1 is hypothesized to be secondary to an underlying vasculopathy.

METHODS

We describe the entity we term NF1-associated PAH (NF1-PAH) in four new patients and update the data on four previously published reports of patients with PAH and NF1. We performed genetic testing of the bone morphogenic protein receptor 2 (BMPR2) gene, which mutated in 70% of patients with familial PAH and approximately 25% of patients with idiopathic PAH. We report, for the first time, pathologic findings in the autopsy-obtained lung of one patient with NF1-PAH.

RESULTS

Patients with NF1-PAH have a generally poor long-term prognosis. In four patients, we observed the mosaic pattern of lung attenuation on a CT scan of the chest, a radiographic finding that can be consistent with an underlying vasculopathy. No mutations or rearrangements in the BMPR2 gene were found. We observed complex plexiform lesions in the one available autopsy specimen. Similar lesions are a hallmark of plexogenic pulmonary arteriopathy and are associated with several severe types of PAH. (Plexiform lesions should not be confused with plexiform neurofibromas, which are distinctive tumors seen in NF1.)

CONCLUSIONS

Our findings suggest that NF1 should be considered as being "associated with PAH as outlined in the Revised Clinical Classification of Pulmonary Hypertension. Understanding the mechanism of PAH in NF1 may inform the pathogenesis of PAH, NF1-PAH itself, and other NF1-associated vasculopathies. The pulmonary vasculature should now be included among the arterial beds affected by NF1 vasculopathy.

Pulmonary hypertension in neurofibromatosis

Two cases of severe pulmonary arterial hypertension in patients with neurofibromatosis are reported. The published research is reviewed. In conclusion, it is suggested that the association between these conditions be recognized in the classification of pulmonary hypertension.

von Recklinghausen Disease Complicated by Pulmonary Hypertension

Two patients with von Recklinghausen disease (neurofibromatosis type 1) were admitted to the hospital because of progressive heart failure. Both patients had prominent pulmonary hypertension revealed on cardiac catheterization. A lung perfusion scan did not show any gross defect. There were no underlying causes of pulmonary hypertension in either patient, such as chronic lung disease, congenital or acquired heart disease, deep vein thrombosis, or systemic hypercoagulable states. There may be an unrecognized association between von Recklinghausen disease and pulmonary hypertension.