Neurofibromatosis type 1 and associated malignancies

An Uncommon Presentation of Pheochromocytoma in Neurofibromatosis Type 1 and the Importance of Long-Term Follow-Up

Neurofibromatosis type 1 (NFT1) is a disease caused by mutations in the tumor suppressor gene NF1. It is associated with a higher incidence of chromaffin cell tumors which are usually adrenal, unilateral and benign. The presence of these tumors during pregnancy is extremely rare and frequently associated with fatal outcomes. We report the case of a female patient with NFT1, who presented with paroxysmal spells of headache, palpitations, dizziness and pre-cordial discomfort, starting immediately after the delivery of her third child. Diagnostic work-up came to reveal a bilateral pheochromocytoma and the patient underwent bilateral adrenalectomy. Over 12 years after the initial surgery, metastatic disease was diagnosed, and a reintervention was performed. This is a rare presentation of bilateral malignant pheochromocytoma in a patient with NFT1, with postpartum occurrence of the first symptoms. This text focuses the important details and challenges found at each stage of diagnosis and follow-up.

Ganglioneuroblastoma in a Child With Neurofibromatosis Type 1: A Case Report and Literature Review

Neurofibromatosis type 1 (NF1) is a genetic condition commonly associated with a predisposition to tumor development. Affected individuals have an increased risk of benign and malignant tumors of the central and peripheral nervous system. Though pediatric patients with NF1 have an increased risk of tumors such as optic gliomas and neurofibromas during childhood, neuroblastic tumors are less often observed in this population. We report a rare case of a 5-year-old female with ganglioneuroblastoma intermixed and known history of NF1 and review the existing literature on the occurrence of ganglioneuroblastoma in pediatric patients with NF1.

Laparoscopic retroperitoneal resection of the duodenal gastrointestinal stromal tumors in neurofibromatosis type 1; Case Report and literature review

Background

Neurofibromatosis type 1, also known as NF1, is a disorder that is passed down in an autosomal dominant manner. It manifests in a wide variety of tumors and affects several organ systems. It is expected that those carrying the NF1 gene will develop a rare mesenchymal tumor known as a gastrointestinal stromal tumor (GIST) more than general population.

Case report

This research discusses a 42-year-old female patient with NF1 who was identified with a duodenal GIST but clinically and radiographically misinterpreted as having a retroperitoneal neurofibroma. She had minimally invasive retroperitoneal laparoscopic surgery to remove the tumor and primary anastomosis of the affected duodenal wall. A spindle cell GIST was entirely excised during surgery, as indicated by the pathologist. As a consequence of dialogue at a multidisciplinary team meeting, the patient was discharged from the hospital on the fourth postoperative day and is presently undergoing regular clinical follow-up.

Conclusion

Anatomically problematic sites, such as the duodenal GIST in NF1 patients, can be treated safely with the laparoscopic retroperitoneal approach even when retroperitoneal neoplasia arises from the intrabdominal structure and protrudes into the retroperitoneal region.

Genotype-Phenotype Correlations in Neurofibromatosis Type 1: Identification of Novel and Recurrent NF1 Gene Variants and Correlations with Neurocognitive Phenotype

Neurofibromatosis type 1 (NF1) is one of the most common genetic tumor predisposition syndrome, caused by mutations in the NF1. To date, few genotype-phenotype correlations have been discerned in NF1, due to a highly variable clinical presentation. We aimed to study the molecular spectrum of NF1 and genotype-phenotype correlations in a monocentric study cohort of 85 NF1 patients (20 relatives, 65 sporadic cases). Clinical data were collected at the time of the mutation analysis and reviewed for accuracy in this investigation. An internal phenotypic categorization was applied. The 94% of the patients enrolled showed a severe phenotype with at least one systemic complication and a wide range of associated malignancies. Spine deformities were the most common complications in this cohort. We also reported 66 different NF1 mutations, of which 7 are novel mutations. Correlation analysis identified a slight significant inverse correlation between age at diagnosis and delayed acquisition of psychomotor skills with residual multi-domain cognitive impairment. Odds ratio with 95% confidence interval showed a higher prevalence of learning disabilities in patients carrying frameshift mutations. Overall, our results aim to offer an interesting contribution to studies on the genotype–phenotype of NF1 and in genetic management and counselling.

Oral Malignant Melanoma in a Patient With Neurofibromatosis Type 1: An Extremely Rare Association

Neurofibromatosis type 1 (NF1) is a genetic disorder associated with high rates of neural crest-derived tumors, both benign and malignant. Many series have identified cutaneous melanoma as a rare tumor among cancers occurring in individuals with NF1 disease, but the mucosal location has to date never been reported. In this paper, we report an oral melanoma occurring in a patient with NF1 disorder, diagnosed at a locally advanced stage, successfully managed by definitive external beam radiotherapy, along with a comprehensive literature review on the melanoma-NF1 association.

Optic Pathway Glioma in Children with Neurofibromatosis Type 1: A Multidisciplinary Entity, Posing Dilemmas in Diagnosis and Management Multidisciplinary Management of Optic Pathway Glioma in Children with Neurofibromatosis Type 1

Introduction

Neurofibromatosis type 1 (NF1) has an incidence of 1 in 2,000 to 3,000 individuals and in 15% is associated with optic pathway glioma (OPG). Given the variability in clinical presentation and related morbidity, a multidisciplinary approach for diagnosis and management of children with NF1 and OPG is required, but often lacks coordination and regular information exchange. Herein we summarize our experience and describe the care pathways/network provided by a multidisciplinary team. The role of the distinct team members is elucidated as well as the care amendments made over time.

Methods

We performed a retrospective single-center observational study, including children treated at our institution between 1990 and 2021. Inclusion criteria were clinical diagnosis of NF1, radiographic and/or histopathological diagnosis of OPG and age below 18 years. Patients being treated elsewhere were excluded from the study. Data was abstracted from each child’s health record using a standardized data collection form. Characteristics of children with NF1 and OPG were described using means (SD) and percentages. Outcomes were determined using Kaplan-Meier estimates.

Results

From 1990 to 2021, 1,337 children were followed in our institution. Of those, 195 were diagnosed with OPG (14.6%), including 94 (48.21%) females and 101 (51.79%) males. Comprehensive data were available in 150 patients. The mean (SD) age at diagnosis was 5.31(4.08) years (range: 0.8–17.04 years). Sixty-two (41.3%) patients remained stable and did not undergo treatment, whereas 88 (58.7%) patients required at least one treatment. The mean (SD) duration of follow up was 8.14 (5.46) years (range: 0.1–25.9 years; median 6.8 years). Overall survival was of 23.6 years (±1.08), comprising 5 deaths. A dedicated NF clinic, including pediatricians and a nurse, provides regular follow up and plays a central role in the management of children with NF1, identifying those at risk of OPG, coordinating referrals to Neuroradiology and other specialists as indicated. All children are assessed annually by Ophthalmology. Comprehensive care was provided by a multidisciplinary team consisting of Dermatology, Genetics, Neuro-oncology, Neuroradiology, Neurosurgery, Ophthalmology and Pediatrics.

Conclusions

The care of children with NF1 and OPG is optimized with a multidisciplinary team approach, coordinated by a central specialty clinic.

The role of frailty in the clinical management of neurofibromatosis type 1: a mixed-effects modeling study using the Nationwide Readmissions Database

OBJECTIVE

Frailty embodies a state of increased medical vulnerability that is most often secondary to age-associated decline. Recent literature has highlighted the role of frailty and its association with significantly higher rates of morbidity and mortality in patients with CNS neoplasms. There is a paucity of research regarding the effects of frailty as it relates to neurocutaneous disorders, namely, neurofibromatosis type 1 (NF1). In this study, the authors evaluated the role of frailty in patients with NF1 and compared its predictive usefulness against the Elixhauser Comorbidity Index (ECI).

METHODS

Publicly available 2016–2017 data from the Nationwide Readmissions Database was used to identify patients with a diagnosis of NF1 who underwent neurosurgical resection of an intracranial tumor. Patient frailty was queried using the Johns Hopkins Adjusted Clinical Groups frailty-defining indicator. ECI scores were collected in patients for quantitative measurement of comorbidities. Propensity score matching was performed for age, sex, ECI, insurance type, and median income by zip code, which yielded 60 frail and 60 nonfrail patients. Receiver operating characteristic (ROC) curves were created for complications, including mortality, nonroutine discharge, financial costs, length of stay (LOS), and readmissions while using comorbidity indices as predictor values. The area under the curve (AUC) of each ROC served as a proxy for model performance.

RESULTS

After propensity matching of the groups, frail patients had an increased mean ± SD hospital cost ($85,441.67 ± $59,201.09) compared with nonfrail patients ($49,321.77 ± $50,705.80) (p = 0.010). Similar trends were also found in LOS between frail (23.1 ± 14.2 days) and nonfrail (10.7 ± 10.5 days) patients (p = 0.0020). For each complication of interest, ROC curves revealed that frailty scores, ECI scores, and a combination of frailty+ECI were similarly accurate predictors of variables (p > 0.05). Frailty+ECI (AUC 0.929) outperformed using only ECI for the variable of increased LOS (AUC 0.833) (p = 0.013). When considering 1-year readmission, frailty (AUC 0.642) was outperformed by both models using ECI (AUC 0.725, p = 0.039) and frailty+ECI (AUC 0.734, p = 0.038).

CONCLUSIONS

These findings suggest that frailty and ECI are useful in predicting key complications, including mortality, nonroutine discharge, readmission, LOS, and higher costs in NF1 patients undergoing intracranial tumor resection. Consideration of a patient’s frailty status is pertinent to guide appropriate inpatient management as well as resource allocation and discharge planning.

Mutation spectrum of the NF1 gene and genotype-phenotype correlations in Turkish patients: Seventeen novel pathogenic variants

OBJECTIVE

Neurofibromatosis type 1 is one of the most common autosomal dominant diseases caused by heterozygous mutation in the NF1 gene. Wide spectrum of NF1-related clinical manifestations and mutation distribution makes genetic counselling difficult.

METHODS

The study enrolled 58 unrelated Turkish patients with clinically suspected NF1 referred to the Department of Medical Genetics. Individuals were eligible if they 1) met at least two of the main National Institutes of Health criteria or 2) had multiple café-au-lait macules as a child.

RESULTS

Fourty-one different disease-causing variants were identified in 42 (72.4%) individuals, including 17 novel variants. Twenty-four (58.2%) of the NF1 patients had de novo variants. Café-au-lait macules were observed in all patients (100%). Intracranial hamartoma was the second most common phenotype, found in 52.3% (22/42) of the patients. Other common manifestations were neurofibromas (35.7%), axillary or inguinal freckling (28.5%), and Lisch nodules (28.5%). Additionally, one patient had intra-abdominal malignant peripheral nerve sheath tumours and another patient underwent surgery for serous papillary ovarian cancer.

CONCLUSION

In conclusion, this study is one of the largest studies from Turkey to investigate the NF1 mutation spectrum and genotype-phenotype correlations.

Establishment of in-hospital clinical network for patients with neurofibromatosis type 1 in Nagoya University Hospital

Neurofibromatosis type 1 (NF1) is a genetic multisystem disorder. Clinicians must be aware of the diverse clinical features of this disorder in order to provide optimal care for it. We have set up an NF1 in-hospital medical care network of specialists regardless of patient age, launching a multidisciplinary approach to the disease for the first time in Japan. From January 2014 to December 2020, 246 patients were enrolled in the NF1 patient list and medical records. Mean age was 26.0 years ranging from 3 months to 80 years. The number of patients was higher as age at first visit was lower. There were 107 males (41%) and 139 females. After 2011, the number of patients has increased since the year when the medical care network was started. Regarding orthopedic signs, scoliosis was present in 60 cases (26%), and bone abnormalities in the upper arm, forearm, and tibia in 8 cases (3.5%). Neurofibromas other than cutaneous neurofibromas were present in 90 cases (39%), and MPNST in 17 cases (7.4%). We launched a multidisciplinary NF1 clinic system for the first time in Japan. For patients with NF1, which is a hereditary and systemic disease associated with a high incidence of malignant tumors, it will be of great benefit when the number of such clinics in Japan and the rest of Asia is increased.

Comparison of Cancer Prevalence in Patients With Neurofibromatosis Type 1 at an Academic Cancer Center vs in the General Population From 1985 to 2020

IMPORTANCE

Neurofibromatosis type 1 (NF1) is a complex genetic disorder that is associated with not only neurofibromas, but also an increased susceptibility to other neoplasms.

OBJECTIVE

To evaluate the prevalence of neoplasia and outcomes among patients with NF1.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted among patients with NF1 at a single academic cancer center from 1985 to 2020 with median (range) follow-up of 2.9 years (36 days to 30.5 years). Of 2427 patients evaluated for NF1, 1607 patients who met the National Institutes of Health consensus criteria for NF1 were included. This group was compared with estimates from Surveillance, Epidemiology, and End Results (SEER) Cancer Statistics Review 1975 to 2015 and SEER participants database unless otherwise specified. Data were analyzed from August 2018 to March 2020.

MAIN OUTCOMES AND MEASURES

Disease-specific survival (DSS) was measured from diagnosis date to date of neoplasm-specific death or censorship and calculated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. Deaths from disease were considered a DSS end point; other deaths were considered censored observations. Secondary outcome measures were comparisons of (1) overall survival of patients with NF1 with neurofibroma neoplasms vs those without nonneurofibroma neoplasms, (2) neoplasm prevalence in the NF1 group vs general population estimates, and (3) age at diagnosis in the NF1 group vs general population estimates for the most common neoplasms in the NF1 group.

RESULTS

Among 1607 patients with NF1, the median (range) age at initial visit was 19 years (1 month to 83 years) and 840 (52.3%) were female patients. Among 666 patients who developed other neoplasms in addition to neurofibromas (41.4%), 295 patients (18.4%) developed glioma and 243 patients (15.1%) developed malignant peripheral nerve sheath tumor (MPNST), the most common neoplasms. Patients with NF1, compared with the general population, developed several neoplasms at a younger mean (SD) age (low-grade glioma: 12.98 [11.09] years vs 37.76 [24.53] years; P < .0001; high-grade glioma [HGG]: 27.31 [15.59] years vs 58.42 [19.09] years; P < .0001; MPNST: 33.88 [14.80] years vs 47.06 [20.76] years; P < .0001; breast cancer: 46.61 [9.94] years vs 61.71 [13.85] years; P < .0001). Patients with NF1 developed neoplasms more frequently compared with the general population (odds ratio, 9.5; 95% CI, 8.5-10.5; P < .0001). Among patients with NF1, significantly lower 5-year DSS rates were found among those with undifferentiated pleomorphic sarcoma (1 of 5 patients [20.0%]), HGG (8 of 34 patients [23.1%]), MPNST (72 of 228 patients [31.6%]), ovarian carcinoma (4 of 7 patients [57.1%]), and melanoma (8 of 12 patients [66.7%]) compared with those who had neoplasms classified as other (110 of 119 patients [92.4%]) (all P < .001) .

CONCLUSIONS AND RELEVANCE

This cohort study found that among patients with NF1, those who developed undifferentiated pleomorphic sarcoma, HGG, MPNST, ovarian carcinoma, or melanoma had significantly lower DSS rates compared with those who developed other neoplasms. This study also found that patients with NF1 developed some neoplasms more frequently and at a younger age compared with individuals without NF1. HGGs and MPNST were noteworthy causes of death among patients NF1. This information may be useful for NF1 patient counseling and follow-up.

The recurrent plexiform neurofibroma of the scalp in neurofibromatosis type 1: illustrative case

BACKGROUND

Plexiform neurofibroma is a benign tumor of the peripheral nerves. It is an unusual variant of neurofibroma originating from all parts of the nerve. Plexiform neurofibroma is primarily pathognomonic and exhibits an unusual variant from neurofibromatosis type 1 (NF1). The possibility of malignancy and recurrence are the main reasons for long-term, close follow-up.

OBSERVATIONS

The authors report a case of a 14-year-old girl with a recurrent plexiform neurofibroma derived from the peripheral nerves, which also presented with a typical sign of NF1 disease. The aim of the tumor resection is symptomatic relief.

LESSONS

Accomplishing a good outcome can be related to good perioperative planning and a precise operative procedure. The result of anatomical pathology determines the prognosis of the patient. Clinical examination and radiological studies are needed to evaluate the recurrence of complications after surgical procedures.

Neurofibromatosis Type 1: A Population-Based Study

PURPOSE

To report the incidence, demographics, and clinical manifestations of neurofibromatosis type 1 among a population-based cohort of patients.

METHODS

The medical records of all patients diagnosed as having neurofibromatosis type 1 while residing in Olmsted County, Minnesota, from January 1, 1980, through December 31, 2009, were retrospectively reviewed.

RESULTS

Fifty patients were diagnosed as having neurofibromatosis type 1 during the 30-year period, yielding an incidence of 1.2 per 100,000 individuals. The mean age at diagnosis was 11.7 years (95% confidence interval [CI]: 0.2 to 47) and 26 (52%) were males. Twenty-eight patients were new mutations, yielding a de novo mutation rate of 56%. During a mean follow-up of 9.8 years (range: 3 weeks to 32 years), café-au-lait macules were diagnosed in 49 individuals (98%), neurofibromas in 26 (52%), and skeletal anomalies in 14 (28%). Three (5.9%) individuals were diagnosed as having glioma of the central nervous system (95% CI: 1.2 to 9.7%) at a mean age of 13 years (range: 5 to 26 years), including 1 patient with optic nerve glioma diagnosed at the age of 26 years. Only 1 (2%) patient was diagnosed as having malignant nerve sheath tumor.

CONCLUSIONS

Although the prevalence and de novo mutation rate of neurofibromatosis type 1 in this population-based study were similar to prior reports, the occurrence of optic nerve gliomas was much lower. [J Pediatr Ophthalmol Strabismus. 2019;56(4):243-247.].

Peripheral nerve injuries in the pediatric population: a review of the literature. Part III: peripheral nerve tumors in children

INTRODUCTION

Peripheral nerve tumors type, inciedence and treatment in the pediatric population should be analyzed.

METHODS

We have performed an extense literature review of this subject.

RESULTS

incidence and distribution are similar to those observed in adults. The most common peripheral nerve tumors in children are neurofibromas and schwannomas. Malignant peripheral nerve sheath tumors are also observed, specially associated with genetic syndromes, like neurofibromatosis and Carney complex.

CONCLUSION

In this review, peripheral nerve tumors have been divided into three categories to aid with understanding: reactive and hyperplastic lesions, benign tumors, and malignant tumors. The most frequent lesions have been described.

Solitary eyelid neurofibroma presenting as tarsal cyst: Report of a case and review of literature

Purpose

To report a rare case of solitary eyelid neurofiboma presenting as tarsal cyst.

Observation

A 64 year old male, presented with a painless, non progressive swelling in the right upper eye lid. Examination revealed a non tender, firm, mass adherent to the underlying tarsus. Excision via a conjunctival approach was performed and the histopathology was suggestive of neurofibroma. Immunohistochemistry was positive for Vimentin and focally positive for S-100. The patient did not have any features of neurofibromatosis.

Conclusion

and Importance: Solitary neurofibroma of the eyelid does not have any systemic association with neurofibromatosis, and only seven such cases have been reported in English literature. We report a case of solitary neurofibroma of the eyelid presenting as tarsal cyst. A thorough review of literature of previously reported cases is included.

NF1 and Neurofibromin: Emerging Players in the Genetic Landscape of Desmoplastic Melanoma

Neurofibromatosis type I (NF1), a monogenic disorder with an autosomal dominant mode of inheritance, is caused by alterations in the NF1 gene which codes for the protein neurofibromin. Functionally, NF1 is a tumor suppressor as it is GTPase-activating protein that negatively regulates the MAPK pathway. More recently, much attention has focused on the role of NF1 and neurofibromin in melanoma as mutations in NF1 have been found to constitute 1 of the 4 distinct genomic categories of melanoma, with the other 3 comprising BRAF, NRAS, and "triple-wild-type" subtypes. In this review, we parse the literature on NF1 and neurofibromin with a view to clarifying and gaining a better understanding of their precise role/s in melanomagenesis. We begin with a historic overview, followed by details regarding structure and function and characterization of neural crest development as a model for genetic reversion in neoplasia. Melanogenesis in NF1 sets the stage for the discussion on the roles of NF1 and neurofibromin in neural crest-derived neoplasms including melanoma with particular emphasis on NF1 and neurofibromin as markers of melanocyte dedifferentiation in desmoplastic melanoma.

Neurofibromatosis type 1 and malignancy in childhood

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.

Uptake of health monitoring and disease self-management in Australian adults with neurofibromatosis type 1: strategies to improve care

Lifelong health monitoring is recommended in neurofibromatosis type 1 (NF1) because of the progressive and unpredictable range of disabling and potentially life-threatening symptoms that arise. In Australia, strategies for NF1 health surveillance are less well developed for adults than they are for children, resulting in inequalities between pediatric and adult care. The aims of this study were to determine the uptake of health monitoring and capacity of adults with NF1 to self-manage their health. Australian adults with NF1 (n = 94, 18-40 years) participated in a semi-structured interview. Almost half reported no regular health monitoring. Thematic analysis of interviews identified four main themes as to why: (i) did not know where to seek care, (ii) unaware of the need for regular monitoring, (iii) futility of health monitoring as nothing can be done for NF1, and (iv) feeling healthy, therefore monitoring unnecessary. Overall, there were low levels of patient activation, indicating that adults with NF1 lacked knowledge and confidence to manage their health and health care. Findings are discussed in the context of service provision for adults with NF1 in New South Wales, Australia.

Malignant peripheral nerve sheath tumors (MPNST): a SEER analysis of incidence across the age spectrum and therapeutic interventions in the pediatric population

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are very rare in the general population and challenging to treat. A paucity of data exists regarding the incidence of MPNST across all age groups and treatment outcomes in the pediatric population. We aimed to characterize both using the Survival, Epidemiology, and End Results (SEER) database.

PROCEDURE

The SEER-18 database with information on the United States population from 1973 to 2009 was queried for cases of MPNST. For incidence data, 1,182 cases were found among the general population. Of those, 165 cases were in individuals aged 0-19. After exclusions, 139 cases from the SEER-18 database met study criteria for outcomes analysis. For each patient, variables including gender, age, race, stage (localized, regional, or distant), surgical treatment, and radiotherapy were obtained.

RESULTS

The overall incidence of MPNST was 1.46 per million person-years, with increased incidence among the elderly. In the pediatric population, the incidence was 0.56 per million person-years, and was higher among post-pubertal children aged 10-19. Median overall survival in the pediatric population was 30 months, with only localized disease and treatment with surgery being positive prognostic factors on multivariate analysis.

CONCLUSIONS

MPNST is a rare disease and, among children, is most frequent seen in adolescents. Surgery is crucial as first-line treatment for MPNST, especially if the tumor is localized at diagnosis. In patients with non-localized MPNST, the disease remains extremely difficult to manage, and both surgery and radiotherapy are interventions that should be considered.

Brainstem gliomas

Historically, brainstem gliomas have been considered as a single entity. Since the introduction of magnetic resonance (MR) imaging in the late 1980s, these tumors are now regarded as a heterogeneous group of neoplasms with different age of onset, clinical and radiologic presentation, and varying behavior and natural history. This article describes the different subtypes of brainstem gliomas in children and adults. We focus on recent advances in MR such as MR spectroscopy, MR perfusion, and diffusion tensor imaging that often strongly suggest the histopathologic diagnosis of the lesion.

A case report of acute myeloid leukemia and neurofibromatosis 1

We report a case of a 65-year old patient affected by neurofibromatosis 1, documented by the presence of germ-line mutation on the NF1 gene, who developed various hyperproliferative malignant and benign diseases. He was brought to our attention for the diagnosis of acute myeloid leukemia revealed by major fatigue and dyspnea. The disease characteristics at diagnosis were hyperleukocytosis and complex karyotype with the inversion of the chromosome 16, classifying as a high-risk leukemia. The association between leukemia and neurofibromatosis 1 is controversial and needs to be further investigated. Nevertheless, such patients present a wide number of comorbidities that make therapeutic strategies most difficult.

Epilepsy surgery in Neurofibromatosis Type 1

Epilepsy is relatively uncommon in patients with Neurofibromatosis Type 1 (NF1) and seizures are usually well controlled with antiepileptic treatment. However, pharmacoresistance has been reported in patients with NF1 and MRI evidence of malformations of cortical development or glioneuronal tumours. Available information on epilepsy surgery in NF1 is limited to a few patients with gliomas and glioneuronal tumours who underwent lesionectomies. We conducted a survey amongst 25 European epilepsy surgery centres to collect patients with NF1 who had undergone surgery for drug-resistant seizures and identified 12 patients from eight centres. MRI abnormalities were present in all patients but one. They were unilateral temporal in eight, bilateral temporal in one and multilobar or hemispheric in two. Seizures originated from the temporal lobe in ten patients, from the temporo-parieto-occipital region in one, and were bitemporal in one. One year after surgery eight patients were seizure free, one had worthwhile improvement and the remaining three had experienced no benefit. Postoperative outcome, available at 2 years in ten patients and at 5 years in three, remained stable in all but one whose seizures reappeared. Histology revealed dysembryoplastic neuroepithelial tumour (DNET) in five patients, hippocampal sclerosis in four, mixed pathology in one and polymicrogyria in one. No histological abnormality was observed in the remaining patient. Epilepsy surgery can be performed effectively in patients with NF1 provided a single and well-delimited epileptogenic zone is recognized. The high prevalence of DNETs in this series might suggest a non-fortuitous association with NF1.

Increased wild-type N-ras activation by neurofibromin down-regulation increases human neuroblastoma stem cell malignancy

Cellular heterogeneity is a well-known feature of human neuroblastoma tumors and cell lines. Of the 3 phenotypes (N-, I-, and S-type) isolated and characterized, the I-type cancer stem cell of neuroblastoma is the most malignant. Here, we report that, although wild-type N-Ras protein is expressed at the same level in all 3 neuroblastoma cell phenotypes, activated N-Ras-GTP level is significantly higher in I-type cancer stem cells. When activated N-Ras levels were decreased by transfection of a dominant-negative N-Ras construct, the malignant potential of I-type cancer stem cells decreased significantly. Conversely, when weakly malignant N-type cells were transfected with a constitutively active N-Ras construct, activated N-Ras levels, and malignant potential, were significantly increased. Thus, high levels of N-Ras-GTP are required for the increased malignancy of I-type neuroblastoma cancer stem cells. Moreover, increased activation of N-Ras results from significant down-regulation of neurofibromin (NF1), an important RasGAP. This specific down-regulation is mediated by an ubiquitin-proteasome-dependent pathway. Thus, decreased expression of NF1 in I-type neuroblastoma cancer stem cells causes a high level of activated N-Ras that is, at least in part, responsible for their higher tumorigenic potential.

Neurogenic tumors of soft tissue

Neurogenic tumors are an uncommon yet important category of soft tissue tumors in children and adolescents because of their frequent association with various genetic syndromes. The heterogeneous cellular composition of the peripheral nerve and the wide metaplastic capacity of the neural crest and its derivatives generate a variety of neoplasms with neurogenic differentiation. This article reviews the clinicopathologic features and differential diagnosis of neurogenic tumors in the first two decades of life, and highlights use of selected ancillary methods for diagnosis.

Free flap reconstruction of extensive defects following resection of large neurofibromatosis

BACKGROUND

Neurofibromatosis type 1 (NF-1) is a locally invasive tumor that can grow extensively with diffuse infiltration into surrounding tissue. Resecting a large neurofibroma can result in an extensive defect that is difficult to reconstruct and can cause both aesthetic and functional deformities.

METHODS

From 2000 to 2010, 5 patients with NF-1 underwent radical resection and immediate reconstruction with 6 free flaps at our institution. All patients presented with recurrent tumor, and involved head and neck region in 4 and foot in 1 patient. Ages ranged from 18 to 75 years. The follow-up ranged from 1 to 94 months.

RESULTS

Defect sizes ranged from 84 to 252 cm. A single free flap was used in 4 cases and 2 free flaps were used in 1 case. All the flaps survived. Complications included loss of skin graft, necrosis of the distal tip of a flap, and wound dehiscence. All complications were successfully managed with minor surgical procedures.

CONCLUSION

Immediate reconstruction using a free flap after resecting a large neurofibroma is a safe and reliable method that facilitates radical resection of the tumors that are difficult to resect and that may result in an extensive defect.

A case of persistent foot pain in a neurofibromatosis type I patient

Introduction. This is the case of a young male patient who presented to his family physician with atypical left foot pain, which was extremely resistant to analgesia and caused significant disability. Despite extensive investigations, the cause of his pain was not identified until 18 months after his initial symptoms, when the official diagnosis of malignant peripheral nerve sheath tumour (MPNST) was made. Detailed review of the patient's past history established the diagnosis of type I neurofibromatosis (NF-1), previously undetected. Discussion. NF-1 is an autosomal dominant genetic disorder caused by loss of function mutations of the NF1 gene in chromosome 17. Patients with this condition are at increased risk for developing MPNSTs which, however, are treatable only in early stages. Conclusion. Although monitoring NF-1 patients for the development of MPNSTs is common practice, the index of clinical suspicion in patients without an established NF-1 diagnosis is low. Any atypical pain in young adults should raise the possibility of this malignancy, and this case illustrates the fact that MPNSTs can be the first manifestation of NF-1 in patients previously undiagnosed with the disease.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Chronic myeloid leukemia in an adult ghanaian with sporadic neurofibromatosis 1

Patients with neurofibromatosis type 1 (NF1), a common, progressive, autosomal dominant neurocutaneous disorder, are predisposed to malignancies. Several types of hematologic malignancies have been described in them. However, to date there has been no report to the best of our knowledge of a patient with NF1 developing chronic myeloid leukemia (CML). We present an adult Ghanaian with NF1, who subsequently developed CML. Relevance of the case report is discussed.

High CD133 expression levels in gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumours (GISTs) have activating KIT or PDGFRA gene mutations. Imatinib mesylate, which targets KIT and PDGFRA, is effective in treating GISTs, but 90% of GIST patients become imatinib-resistant as a result of acquiring secondary KIT mutations. Recent findings suggest that tumour growth can be driven by mutated self-renewing progenitors known as cancer stem cells (CSCs), which are believed to be present in all neoplastic proliferations and are thought to accumulate mutations. It is therefore possible that the acquisition of secondary KIT mutations during imatinib treatment may occur in putative GIST CSCs.

METHODS

Using flow cytometry, in vivo murine xenografts and molecular characterization, we tried to identify putative GIST CSCs by looking for the occurrence of common CSC markers such as KIT, CD133, CD90, CD44, and CD34 in 18 surgical samples obtained from nine untreated and nine imatinib-treated KIT-mutated GIST patients.

RESULTS

The results indicated the homogeneous and previously unreported expression of CD133 (18/18), CD90 (15/16), and CD44 (12/14), together with KIT (18/18) and CD34 (13/18). This profile is similar to that identified in bone marrow mesenchymal progenitors and does not seem to be significantly modified by imatinib as only marginal changes in KIT and CD133 expression (P ≤ 0.05, Mann-Whitney test) were found in the treated samples.

CONCLUSIONS

These findings suggest that GISTs are a clonal expansion of quite primitive cells that strictly depend on KIT oncogenic addiction, and have no cancer/stem cell component that can be detected by means of the antigens used in this study.

Orthopaedic aspects of neurofibromatosis: update

PURPOSE OF REVIEW

Neurofibromatosis type I (NF-1), affecting 1: 3000 people, is one of the most common disorders of the nervous system, and most pediatricians will care for a patient with this condition. It is imperative that careful attention be paid to screening for scoliosis and tibial dysplasia. Prompt referral to an orthopaedist at the time of diagnosis, as well as neurologist, ophthalmologist, and dermatologist, will provide a global spectrum of care for the individual. Patient care between surgical procedures will be inevitable, with 70% of patients with NF-1 undergoing hospitalization or surgery.

RECENT FINDINGS

This review provides a description of diagnosis, presurgical evaluation, and advances in understanding tibial dysplasia, scoliosis and malignant peripheral nerve sheath tumors. New pharmaceutical treatments such as lovastatin have improved bone healing in vivo and induced apoptosis in vitro. Multiple pharmaceuticals have shown neurofibroma arrest in vitro and are in phase II clinical trials.

SUMMARY

As animal models improve and clinical trials proceed, there is momentum toward eliminating the musculoskeletal morbidity associated with NF-1.

Heritability of hematologic malignancies: from pedigrees to genomics

Many hematologic malignancies have an underlying heritable component. Although not as well characterized as the acquired genetic abnormalities that define important prognostic and therapeutic subgroups of myeloid and lymphoid neoplasms, investigations are beginning to unravel the role of germline genetic variation in the predisposition to hematologic malignancies. Information gained from the study of striking family pedigrees, epidemiologic data, and candidate genes are now being combined with unbiased genome-wide investigations to outline the network of genetic abnormalities that contribute to hematologic malignancy risk. This article reviews the current understanding of the heritability of hematologic malignancies in the genomics era.