Vertebral column resection (VCR) at the subapical vertebra for correction of angular kyphosis associated with neurofibromatosis type 1(NF1): a case report

PURPOSE

To describe the process and outcome of vertebral column resection (VCR) at the subapical vertebra for correction of angular kyphosis associated with neurofibromatosis type 1(NF1).

METHODS

A review and summary of the medical history, radiographs, operative procedure, and complications of a 16-year-old male presenting with severe angular kyphosis associated with NF1 with dyspnea.

RESULTS

A 16-year-old male presented with severe angular kyphosis associated with NF1 with dyspnea. Preoperative radiographs demonstrated multiple vertebrae were rotated in the vicinity of the apical vertebra, with a wedge-shaped deformity, dysplasia, T10-T12 kyphotic angle of 160°, and T2-L2 kyphotic angle of 95°. VCR at the L1 vertebra (distal end of the apical vertebra) with bone grafting and internal fixation was performed. Postoperative imaging revealed that the T2-L2 Cobb angle was 20°, denoting a correction rate of 79%. The patient's height increased from 130 to 150 cm. The position of internal fixation was not displaced, and the correction angle was maintained at 2-year follow-up.

CONCLUSIONS

The novel strategy of performing VCR at the subapical vertebra, with posterior displacement of the distal end, and remodeling of the spinal canal is potentially a safe and efficacious option to correct sharp angular kyphosis.

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.

Atypical Neurofibromatous Neoplasm with Uncertain Biologic Potential in the Posterior Mediastinum of a Young Patient with Neurofibromatosis Type 1: A Case Report

Atypical neurofibromatous neoplasm with unknown biological potential (ANNUBP), proposed in a recent NIH consensus overview, is a rare precursor entity of malignant peripheral nerve sheath tumor (MPNST) in neurofibromatosis type 1 (NF1) patients. Only one report on imaging findings of ANNUBP is available. Herein, we present the case of a 19-year-old female, diagnosed with a mediastinal tumor by chance, who visited to our hospital. She had café-au-lait spots on her trunk and a past history of resected neurofibroma. Her family also had café-au-lait spots; therefore, an NF1-induced tumor was strongly suspected. MRI revealed a paravertebral mass of 7.5 cm in size consisting of an inner rim with low T2 signal intensity and an outer rim with high T2 intensity, which was similar to a target sign, adjacent to the pulmonary veins; the center of the tumor was well enhanced by gadolinium, and the peripheral region was myxoid and slightly enhanced. FDG-PET showed high FDG uptake, SUVmax of 8.5, although the peripheral region represented low FDG accumulation. CT-guided needle biopsy was repeated because of the suspicion of an MPNST, which resulted in the histopathological diagnosis of ANNUBP. Marginal tumor resection was performed, and the final post-resection histopathological diagnosis was ANNUBP transformed from neurofibroma; the region of ANNUBP lost p16 immunostaining, although it was retained in the peripheral region of the neurofibroma. There has been no recurrence or metastasis 1 year after treatment. In conclusion, ANNUBP could be represented as a well-enhanced homogeneous mass on MRI and a high FDG accumulated region on FDG PET/CT, as seen in MPNST, in NF1 patients.

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.

Multiplatform molecular analyses refine classification of gliomas arising in patients with neurofibromatosis type 1

Gliomas arising in the setting of neurofibromatosis type 1 (NF1) are heterogeneous, occurring from childhood through adulthood, can be histologically low-grade or high-grade, and follow an indolent or aggressive clinical course. Comprehensive profiling of genetic alterations beyond NF1 inactivation and epigenetic classification of these tumors remain limited. Through next-generation sequencing, copy number analysis, and DNA methylation profiling of gliomas from 47 NF1 patients, we identified 2 molecular subgroups of NF1-associated gliomas. The first harbored biallelic NF1 inactivation only, occurred primarily during childhood, followed a more indolent clinical course, and had a unique epigenetic signature for which we propose the terminology "pilocytic astrocytoma, arising in the setting of NF1". The second subgroup harbored additional oncogenic alterations including CDKN2A homozygous deletion and ATRX mutation, occurred primarily during adulthood, followed a more aggressive clinical course, and was epigenetically diverse, with most tumors aligning with either high-grade astrocytoma with piloid features or various subclasses of IDH-wildtype glioblastoma. Several patients were treated with small molecule MEK inhibitors that resulted in stable disease or tumor regression when used as a single agent, but only in the context of those tumors with NF1 inactivation lacking additional oncogenic alterations. Together, these findings highlight recurrently altered pathways in NF1-associated gliomas and help inform targeted therapeutic strategies for this patient population.

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.

Radiographic characteristics of the maxillomandibular complex in neufibromatosis: short communication and literature review

OBJECTIVE

To report radiographic characteristics of a case of a patient with neurofibromatosis involving the maxillomandibular complex and to point out other dental radiographic characteristics that are found in the scientific literature to help the dentist when faced with a case of neurofibromatosis.

SHORT COMMUNICATION

Male, 31 years old, referred for radiographic examination. During anamnesis and physical examination, lesions were noted, which were papules and café-au-lait patches larger than 1 cm on the trunk and upper limbs, further to Lisch nodules (brown spots on the iris) and axillary and inguinal ephelides. When investigating the history of the disease, the patient reported the presence of such skin atlterations since birth and mentioned that his mother had been diagnosed with neurofibromatosis. During radiographic evaluation, a significant increase in the caliber of the mandibular canal and mental foramen was observed, bilaterally.

CONCLUSION

Completing the combination of skin characteristics present in the patient, anamnesis data and current history of the disease with interpretation of radiographic alterations, it was possible to arrive at the diagnostic hypothesis of Neurofibromatosis type 1 and correct clinical management. Therefore, it is extremely important for the dentist to be aware of the clinical, physical and radiographic characteristics that this condition presents for the correct management and success of dental treatment.

[Treatment and progress of cutaneous neurofibroma]

OBJECTIVE

To summarize current widely-used therapies for cutaneous neurofibroma (cNF) and related research progress.

METHODS

Based on extensive investigation of domestic and foreign research, the existing treatment of cNF, including the indications, effectiveness and trials of targeted drugs were reviewed.

RESULTS

cNF is a hallmark feature of neurofibromatosis type 1 and has a dramatic negative impact on patient appearance and quality of life. At present, there is no standard management of cNF. Invasive treatment is a commonly-used treatment. Surgical removal gives excellent cosmetic results, but it is difficult for multiple tumors; CO₂ laser ablation, laser photocoagulation, electro-drying, and radiofrequency ablation are effective in treating lots of cNF at one time. Although fast and effective, these therapies can lead to depigmentation, hyperpigmentation, or extensive scarring. There is no targeted drug approval for cNF, and a series of studies have been carried out on the Ras-MEK pathway, Ras-mTOR pathway, receptor tyrosine kinase, et al.

CONCLUSION

The treatment of cNF has developed rapidly in recent years and has broad prospects, but the individualization and precision of the treatment still needs further clinical research.

Evaluation of the impact of the 2021 revised Neurofibromatosis type 1 diagnostic criteria on time to diagnosis

Neurofibromatosis type 1 (NF1) has historically been diagnosed clinically based on the NIH Consensus Conference diagnostic criteria. The molecular and clinical knowledge of NF1 has subsequently improved, and an international group of experts published revised diagnostic criteria in 2021, incorporating new diagnostic criteria such as pathogenic variants in NF1. This study aimed to investigate the impact of these new diagnostic criteria on time to diagnosis (TTD) of NF1. A retrospective chart review of individuals evaluated for a diagnosis of NF1 at the Medical Genetics Clinic at Stanford Children's Health was performed. The TTD was determined by calculating the days between their first visit with a medical geneticist for NF1 and the date they would have received a diagnosis based on the previous NF1 diagnostic criteria and the 2021 updated diagnostic criteria. The revised diagnostic criteria for NF1 decreased TTD. The mean difference in TTD was 113 days shorter for the new criteria (p-value = 1.306x^-05 ). This study highlights that the revised 2021 NF1 diagnostic criteria can decrease the TTD. The addition of a heterozygous pathogenic variant in NF1 as a criterion was the change that decreased TTD.

A novel mutation of the NF1 gene in a Chinese family with neurofibromatosis type 1

BACKGROUND

Mutations in the neurofibromin 1 (NF1) gene are associated with clinical manifestations of neurofibromatosis type 1 (NF1).

OBJECTIVE

To clarify the relationship between NF1 variants and disease phenotype.

METHODS

Peripheral blood samples were collected from a patient and her relatives and genomic DNA was extracted for next-generation sequencing (NGS) to detect potential variants; the results were validated by Sanger sequencing.

RESULTS

A novel frameshift variant c.4508_c.4509delAT (p.Asn1503fsTer26) was detected in exon 34 of the NF1 gene in the patient and her daughter, but not in any other (healthy) family member. This c.4508_c.4509delAT (p.Asn1503fsTer26) frameshift variant of NF1 may underlie NF1 in this family.

CONCLUSIONS

This finding expands the spectrum of pathogenic mutations of the NF1 gene, which could aid genetic counseling and prenatal diagnosis.

Neurofibromatosis type 1: A comparison of the 1997 NIH and the 2021 revised diagnostic criteria in 75 children and adolescents

PURPOSE

Examining a cohort of patients suspicious of neurofibromatosis type 1 (NF1) we compared the revised diagnostic criteria with the previous National Institutes of Health (NIH) diagnostic criteria. We asked whether the refinement improved distinguishing between NF1, Legius syndrome, and constitutional mismatch repair deficiency (CMMRD).

METHODS

A database search in the hospital information system of the University Children's Hospital Augsburg between 2017 and 2020 ascertained patients with International Classification of Diseases-10 code Q85.0; their clinical phenotype was evaluated by retrospective chart review.

RESULTS

A total of 75 patients were identified (median age 11.0 years [range 1.1-22.6 years]; 35 female). At first suspicion of NF1, 44 patients met the NIH criteria and 56 met the revised diagnostic criteria. In total, 12 patients were diagnosed with NF1 after performing molecular genetic testing. In 31 patients, only pigmentary findings were present, whereas nonpigmentary NF1 manifestations presented with time in 9 patients. In 1 patient a heterozygous variant of uncertain significance was identified in SPRED1. Requirements for CMMRD testing were fulfilled in another patient. A total of 3 patients presented with segmental clinical findings. Three additional patients did not meet the NIH criteria, 1 of them presented with 1 additional feature of CMMRD without fulfilling requirements for testing.

CONCLUSION

In our pediatric cohort, the revised diagnostic criteria discovered more patients with proven NF1 than the NIH criteria.

Bone deformities in patients with neurofibromatosis type 1: Single-center experience

BACKGROUND

Neurofibromatosis type 1 (NF-1) is the most common neurocutaneous syndrome with an autosomal dominant inheritance. However, half of the cases are de novo mutations. Involvement of bone, skin (cafe au lait macules), as well as ocular and tumoral formations is also associated with NF-1. Here, we present our case series of patients with bone deformities.

METHODS

The medical files of patients with NF-1 who were followed up by the same doctor in the pediatric neurology outpatient clinic over 2 years were retrospectively analyzed.

RESULTS

Overall, 19 girls and 13 boys were diagnosed with NF-1. Of these 32 patients, 12 (nine girls, three boys) were found to have bone pathologies. The average age was of these patients with bone pathology was 7.5 and 9.5 years. Scoliosis, bowing, short stature, and long bone cysts were found in descending order of frequency. Severe adhesions in the hands and feet as well as phalangeal hypoplasia were noted in one patient.

CONCLUSION

NF-1 requires a multidisciplinary approach. Routine follow-up is very important as it is known that deformities that affect different systems may appear or increase with age. Severe hand and foot anomalies seen in one of our patients did not seem to be associated with NF-1.

RETRACTED: A case report of a 4-year-old girl with neurofibromatosis type 1

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors. A diagnostic discordance in the original pathology reports has been noticed and requires further evaluation, therefore the paper will be retracted.

Recurrent Mandibular Giant Cell Lesion in Neurofibromatosis Type 1: Second Hit Mutation on the NF1 Gene in the Osseous Lesion

BACKGROUND/AIM

In the autosomal dominant hereditary disease neurofibromatosis type 1 (NF1), lesions of the jaw develop in isolated cases, which are diagnosed as central giant cell granuloma (CGCG). This study aimed to clarify the genetic basis of a bone lesion in a syndromic patient.

CASE REPORT

The NF1 patient had developed a CGCG that recurred after local excision. Blood and tumor tissue were studied for NF1 mutations using advanced molecular genetic methods. Examinations of blood and tumor tissue provided evidence of the constitutive mutation in both samples. A further mutation was detected in the tumor, which was interpreted as a somatic mutation. The detection of somatic mutation in the tissue was successful both on native and routinely fixed material.

CONCLUSION

The study supports current assessments of CGCG as a benign neoplasm. In NF1 patients, the phenotype seems to imply bi-allelic loss of the NF1 gene. The detection of both mutations in routinely fixed tissue allows studies of archived tissue samples with this diagnosis.

[Clinical aspects of Neurofibromatosis type 1 seen in the Department of Dermatology at University Hospital Antananarivo, Madagascar]

INTRODUCTION

Neurofibromatosis 1 (NF1) is an inherited disease, in an autosomal dominant manner, with complex multi-system involvements. Prevalence varies from one country to another. However, little is known about neurofibromatosis in African countries, particularly in Madagascar.

METHODOLOGY

A descriptive retrospective study from 2014 to 2019 was conducted at the service of dermatology at University Hospital Joseph Raseta Befelatanana in Antananarivo, including all patients with neurofibromatosis according to National Institutes of Health Consensus Conference criteria for whom genealogical investigation could be made.

RESULTS

Among 32 cases of NF1 seen during 6 years, 28 cases were included with a sex ratio M/F of 0.87. The mean age was 24 years ranging from 11 to 54 years. Seventeen patients presented sporadic forms. All patients had "café au lait" spots and cutaneous neurofibromatosis. Three cases presented plexiform neurofibromas which cause significant cosmetic and functional problems by their size and their displayed topography. Fifteen patients had Lisch nodules but no case of optic glioma was identified. Neurological symptoms such as learning difficulties, epilepsy and headache were frequent in our case series. However, access to medical imaging was very limited. Scoliosis was the most common orthopedic complication.

CONCLUSION

The clinical manifestations of NF1 are extremely variable. Although the possibility of systemic complications seems to be low, patients must be followed up.

Transition to adult care of young patients with neurofibromatosis type 1 and cognitive deficits: a single-centre study

BACKGROUND

The transition of adolescents to adult care is known to be challenging. Studies indicate that patients with a chronic disease and cognitive deficits are at risk of inadequate transition to adult care, which eventually may result in disease deterioration. This study investigated the transition process for patients with neurofibromatosis type 1 (NF1) and discussed whether patients with NF1 and cognitive deficits should receive additional attention in their transitional period.

METHOD

A self-reported online questionnaire assessing disease severity, cognitive deficits, psychiatric diagnoses as well as transition experiences was completed by patients with NF1 aged 15-25-years. Patients were assigned to a national NF1 expert centre covering the western part of Denmark. Furthermore, a retrospective medical chart review was performed, and data were collected to estimate the prevalence of psychiatric diagnoses.

RESULTS

The questionnaire was completed by 41/103 (39%), median age 20 [range 15; 25] years. Medical chart review was performed in 103 patients, median age 20 [range 15; 25]. Participants reporting the transition as difficult all received special needs education, six reported executive function deficits and three out of seven had a psychiatric diagnosis. Fifteen (37%) questionnaire participants reported a wish for more information about the natural history and the prognosis of NF1. The prevalence of psychiatric diagnoses was 24% in the questionnaire survey and 30% in the medical chart review.

CONCLUSION

This study suggests a need of additional care for patients with NF1 and cognitive deficits including psychiatric disorders during their transition to adult care. In addition, it suggests a need for more information on and education in long-term prospects and mental health issues for patients with NF1.

Increased serum concentrations of estrogen-induced growth factors Midkine and FGF2 in NF1 patients with plexiform neurofibroma

Neurofibromatosis type 1 (NF1) predisposes to the development of dermal and plexiform neurofibromas and serum of NF1 patients stimulates neurofibroma proliferation in vitro. This study aimed to determine whether, in NF1 patients, serum levels of midkine (MK) and fibroblast growth factor 2 (FGF2) were associated with the number and/or type of neurofibromas. In addition, their concentrations were correlated with serum levels of dehydroepiandrosterone sulfate (DHEAS), a neurosteroid secreted by the peripheral nervous system. We performed a case control-study and measured, by ELISA assay, serum concentrations of MK, FGF2, and DHEAS in 20 NF1 patients and 30 controls. We found increased serum levels of MK and FGF2 in NF1 patients between 30 and 50 years old. Their concentrations were significantly higher in NF1 patients with plexiform neurofibromas than in controls (P=0.003 for MK and P=0.008 for FGF2). As an underlying hormonal regulation was suspected, DHEAS serum levels were measured but no difference was observed between patients and controls. We also observed a strong association between MK and FGF2 levels (P=0.0001) in NF1 patients and controls. In conclusion, we point out MK and FGF2 as biomarkers for plexiform neurofibroma in NF1 patients. As both growth factors are estrogen-responsive genes and neurofibromin is a co-repressor of estrogen receptor alpha activity, we suggest that the increased serum levels of MK and FGF2 observed in NF1 patients might be due to estradiol hypersensitivity.

Visual-processing deficits in children with neurofibromatosis type 1: A clinical marker of reading difficulties

Today's estimates indicate that nearly 50% of children with Neurofibromatosis type 1 (NF1) suffer from reading disabilities, with a high impact on their academic achievement. In addition to the well-documented importance of phonological skills in reading acquisition and neurodevelopmental disorders, visual-attention processes also appear as important factors in learning to read. The present study aimed at assessing the role of visual-processing dysfunction in the high prevalence of reading disabilities in NF1 children and providing a useful tool for clinician in the early detection of reading impairment in this neurogenetic disorder. Forty-two children with NF1 and 42 typically developing children (TD) participated in the study. All were right-handed and did not present intellectual disability or attention deficit hyperactivity disorder. Visual-attention processes were assessed with the Developmental Eye Movement (DEM) test, together with the NF1 children's reading level. NF1 children with and without reading disabilities were then compared. The results showed that visual-processing deficits were highly present among the NF1 children included in our study. Furthermore, poor readers with NF1 presented an increased risk of visual-processing deficits compared to peers. This finding supports the role of visual-processing deficits in the reading difficulties encountered in nearly half of children with NF1. Finally, in NF1 children without intellectual or attention disability, visual-processing deficits emerge as one of the clinical markers of reading disabilities. The study holds important clinical implications both for the identification, by providing a useful screening tool, and the management of reading disabilities in NF1 children.

Posterior-Anterior Cephalometric Study of Neurofibromatosis Type 1 Patients With Facial Plexiform Neurofibroma: Analysis of Skeletal Symmetry Concerning Midfacial and Skull Base Reference Points (Zygomatic Arch, Mastoid, and Juga)

BACKGROUND/AIM

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that is also characterized by skeletal abnormalities. In the cranial region, skeletal dysplasia is observed that is associated with a characteristic peripheral nerve sheath tumor, the plexiform neurofibroma (PNF). The aim of the study was to determine PNF-associated skeletal asymmetries of the mid-skull and skull base as an indicator of local tumor development.

PATIENTS AND METHODS

The distances of the zygomatic arch, mastoid, and juga measurement points from the interorbital horizontal plane and median sagittal plane were examined on anterior-posterior cephalograms of 168 NF1 patients (females: 82, males: 86) and compared with the findings of a control group. A distinction was made as to whether the patients had developed a facial PNF.

RESULTS

The distances of the measurement points from the reference planes differed between the patient and control group (p<0.05). Within the NF1 patients, differences between certain distances were noted when comparing patients with PNF and without PNF (p<0.05). In PNF patients, discrete changes in the skull contour were also detectable on the non-affected side (p<0.05). The caudal measurement point of the skull base showed no changes in the group comparison.

CONCLUSION

The individually very variable facial PNF in NF1 is associated with deformations and misalignments of midfacial bones that follow a pattern quantifiable with cephalometric analysis.

Is There a Tendency for Autoimmunity in Neurofibromatosis Type 1? -Case Reports

Autoimmune diseases have been reported in association with neurofibromatosis type 1 (NF1) in adults. Two children with NF1 and concurrent autoimmune diseases: antimuscle-specific kinase antibody-positive myasthenia and juvenile idiopathic arthritis are reported. The possible mechanisms of autoimmunity in NF1, particularly dysregulation in T lymphocyte proliferation and exposure to free DNA were discussed. In clinical practice, the possibility of a superposed disorder is to be considered, particularly on the background of a common clinical condition like NF1.

ERBB2 and ERBB3 Growth Factor Receptors, Neuregulin-1, CD44 and Ki-67 Proliferation Index in Neurofibromatosis Type 1-associated Peripheral Nerve Sheath Tumors

AIM

To characterize the growth pattern and antigen profile of peripheral nerve sheaths tumors (PNST) in a large series of tumors obtained from patients with neurofibromatosis type 1 (NF1).

MATERIALS AND METHODS

Tissue micro-array technique was applied to study 520 PNSTs of 385 patients with NF1 by immunohistochemistry for human epidermal growth factor receptors erb-b2 receptor tyrosine kinase 2 (ERBB2) and ERBB3, CD44, neuroregulin (NRG1) and proliferation index by Ki-67. PNSTs were classified as cutaneous neurofibroma (CNF) in 114 cases, diffuse neurofibroma (DNF) in 109, diffuse plexiform neurofibroma (DPNF) in 108, plexiform neurofibroma (PNF) in 110, and malignant PNST (MPNST) in 22.

RESULTS

The Ki-67 proliferation index was significantly higher in MPNST than in benign PNST (p<0.001). ERBB2 expression was significantly lower in PNST with diffuse growth than in PNF and MPNST (p<0.001). ERBB3 expression was also higher in PNF and MPNST (both p<0.001) than in diffuse PNST. NRG1 expression was significantly higher in PNF than in non-encapsulated benign PNST or MPNST (both p<0.001). Co-expression of ERBB2, ERBB3 and ligand NRG1 was rare, mainly observed in PNST with a plexiform component (in four PNFs, nine DPNFs, one CNF, and two MPNSTs). Expression of CD44 in contrast was significantly stronger in diffusely growing PNST than in PNF (p<0.001).

CONCLUSION

Growth factor receptors ERBB2 and ERBB3 were significantly up-regulated in PNF and MPNST. The antigen expression pattern of DPNF resembled that of benign PNST with diffuse growth pattern rather than that of encapsulated PNF. Differentiating PNST may be important for the assessment of neurofibroma progression, and for the expected impact of drugs currently used for tumor reduction.

Sex- and age-related differences in autistic behaviours in children with neurofibromatosis type 1

This study investigated sex and age differences in autistic behaviours in children with neurofibromatosis type 1 (NF1) who scored within the clinical range on the Social Responsiveness Scale - Second Edition (T score ≥ 60). Thirty-four males and 28 females (3-16 years) were assessed with the Autism Diagnostic Observation Schedule - Second Edition and Autism Diagnostic Interview - Revised. Across both measures, males exhibited greater social communication deficits relative to females. Age-related abatement of social communication difficulties was observed for males but not females. Conversely, no sex differences were found for restricted/repetitive behaviours, which were stable over time for both males and females. The findings are discussed within the context of broader neurodevelopmental considerations that are common in NF1.

Ocular Ischemic Syndrome due to Internal Carotid Artery Occlusion with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF-1) is associated with multiple vascular abnormalities, including internal carotid artery (ICA) stenosis/occlusion. Depending on the site of stenosis/occlusion of the ICA, both cerebral circulation and ocular circulation can be impaired. We describe a rare pediatric case of ocular ischemic syndrome (OIS) due to ICA occlusion in NF-1. The patient diagnosed with NF-1 suffered right ICA occlusion at 12 years of age, and developed right dense vitreous hemorrhage due to OIS at 13 years of age. The patient underwent right cerebral revascularization surgery to improve cerebral and ocular ischemia, but the visual acuity of the right eye did not improve. This case suggests that attention should be paid not only to cerebral ischemia but also to ocular ischemia in patients with ICA stenosis/occlusion of NF-1. Surgical interventions such as cerebral revascularization surgery should be considered in the early stages of OIS to protect visual function, and careful follow-up is required.

Age-dependent oral manifestations of neurofibromatosis type 1: a case-control study

Introduction

Most craniofacial manifestations of neurofibromatosis type 1 (NF1) are considered as a result of tumor compression. We sought to determine salivary changes, caries, and periodontal complications in NF1 patients without tumors in the oral cavity.

Objective and methods

Eleven NF1 patients without tumors in the oral cavity and 29 matched controls without NF1 were enrolled in this case–control study. Demographic information, medical history, and data of intraoral examinations, including the Decayed, Missing, and Filled Teeth (DMFT) scores and Russel’s periodontal index (PI), were recorded. The functional salivary analysis was performed for sialometry, salivary pH values, and amylase activity. Ingenuity Systems Pathway Analysis (IPA) was conducted to identify mutually activated pathways for NF1-associated oral complications.

Results

NF1 patients were associated with periodontitis (OR = 1.40, 95% CI = 1.06–1.73, P = 0.04), gingivitis (OR = 1.55, 95% CI = 1.09–2.01, P = 0.0002), and decreased salivary flow rates (OR = 1.40, 95% CI = 1.05–1.76, P = 0.005). Periodontal destruction, salivary changes, and dental caries in NF1 patients were age-dependent. Subgroup analyses based on age stratification suggested that salivary flow rates and salivary amylase activities were significantly low in NF1 patients aged over 20 years and that salivary pH values, PI and DMFT scores were significantly high among NF1- controls aged over 20. All oral complications were not significantly presented in NF1 patients aged below 20 years. IPA analyses suggested that cellular mechanisms underlying NF1-associated oral complications involved chronic inflammatory pathways and fibrosis signaling pathway.

Conclusion

NF1 patients without tumors in the oral cavity presented a comparatively high prevalence of age-dependent oral complications, including periodontal destruction and salivary gland dysfunction, which were associated with chronic inflammatory pathogenesis.

Atypical connectivity in the cortico-striatal network in NF1 children and its relationship with procedural perceptual-motor learning and motor skills

Introduction

Neurofibromatosis type 1 (NF1) is considered a model of neurodevelopmental disorder because of the high frequency of learning deficits, especially developmental coordination disorder. In neurodevelopmental disorder, Nicolson and Fawcett formulated the hypothesis of an impaired procedural learning system that has its origins in cortico-subcortical circuits. Our aim was to investigate the relationship between cortico-striatal connectivity and procedural perceptual-motor learning performance and motor skills in NF1 children.

Methods

Seventeen NF1 and 18 typically developing children aged between 8 and 12 years old participated in the study. All were right-handed and did not present intellectual or attention deficits. In all children, procedural perceptual-motor learning was assessed using a bimanual visuo-spatial serial reaction time task (SRTT) and motor skills using the Movement Assessment Battery for Children (M-ABC). All participants underwent a resting-state functional MRI session. We used a seed-based approach to explore cortico-striatal connectivity in somatomotor and frontoparietal networks. A comparison between the groups’ striato-cortical connectivity and correlations between connectivity and learning (SRTT) and motor skills (M-ABC) were performed.

Results

At the behavioral level, SRTT scores are not significantly different in NF1 children compared to controls. However, M-ABC scores are significantly impaired within 9 patients (scores below the 15th percentile). At the cerebral level, NF1 children present a higher connectivity in the cortico-striatal regions mapping onto the right angular gyrus compared to controls. We found that the higher the connectivity values between these regions, differentiating NF1 and controls, the lower the M-ABC scores in the whole sample. No correlation was found for the SRTT scores.

Conclusion

NF1 children present atypical hyperconnectivity in cortico-striatal connections. The relationship with motor skills could suggest a sensorimotor dysfunction already found in children with developmental coordination disorder. These abnormalities are not linked to procedural perceptual-motor learning assessed by SRTT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09428-y.