Identification of growth hormone receptor in plexiform neurofibromas of patients with neurofibromatosis type 1

Brachial plexus peripheral nerve sheath tumors (PNSTs): clinical and surgical management in the pediatric population

PURPOSE

Peripheral nerve sheath tumors (PNSTs) are rare in pediatric patients, especially in the brachial plexus. Research on PNSTs is lacking. This article presents a retrospective cohort study of pediatric patients diagnosed and treated with PNSTs, specifically brachial plexus tumors.

METHODS

All pediatric patients intervened in a single center between 2007 and 2023 with brachial plexus tumors were systemically analyzed.

RESULTS

Eleven pediatric patients with 14 brachial plexus PNSTs were studied. The gender distribution was 64% female and 36% male, with an average age of 10.7 years. Ninety-one percent had a previous NF-1 diagnosis. Right brachial plexus presented a higher prevalence (64%). Pain, Tinel's sign, and stiffness masses were common during diagnosis. Motor deficits were noted in 43% of the patients. Surgery was indicated for symptoms, particularly pain and rapid growth, increasing malignancy risk. Due to suspected malignancy, an en bloc resection with safety margins was performed. Among the patients, 57% received a histopathological diagnosis of MPNST (malignant peripheral nerve sheath tumor). Treatment included radiotherapy and chemotherapy. Clinical follow-up was conducted for all cases, involving clinical and oncological evaluations for all MPNSTs.

CONCLUSIONS

This article present a series of pediatric brachial plexus tumors, especially in NF-1, and emphasizes the importance of thorough evaluation for this group. Swift diagnosis is crucial in pediatrics, enabling successful surgery for small lesions with limited neurological symptoms, improving long-term outcomes. Prompt referral to specialized services is urged for suspected masses, irrespective of neurological symptoms. Benign tumor postsurgical progression shows better outcomes than MPNSTs, with complete resection as the primary goal. Needle-guided biopsy is not recommended.

Head circumference and anthropometric changes and their relation to plexiform and skin neurofibromas in sporadic and familial neurofibromatosis 1 Brazilian adults: a cross-sectional study

BACKGROUND

Neurofibromatosis 1 (NF1) is a common autosomal dominant syndrome with complete penetrance and highly variable expressivity. The cutaneous neurofibroma (Cnf) and plexiform neurofibroma (Pnf), café-au-lait spots, and freckle-like lesions are common in NF1, but many other manifestations can occur. We aimed to evaluate head circumference, height, weight, body mass index (BMI), head circumference-to-height ratio (HCHR) and waist-hip ratio (WHR) in adult NF1 Brazilian individuals versus a paired control group and investigate their correlation with the presence of clinically visible Pnfs, and number of "skin neurofibromas" (Snf), which include both cutaneous and subcutaneous neurofibromas.

METHODS

A case-control study was conducted with 168 individuals, 84 with NF1 and 84 without NF1, paired by sex and age. Head circumference and anthropometric measurements, Snf quantification, evaluation of clinically visible Pnf and familial inheritance were accessed.

RESULTS

Prevalence of macrocephaly was significantly higher in NF1 women. Height and weight were significantly lower in both males and females with NF1. HCHR was higher in the NF1 group than in the control group for both sexes. BMI was significantly lower in men with NF1. Waist and hip circumferences were significantly reduced in NF compared with the controls, but the mean WHR was significantly lower only in NF1 women. No correlation was found between the Snf and head circumference and anthropometric measurements, sex or family history. The presence and larger size of clinically visible plexiform neurofibromas were associated with normal stature (p = 0.037 and p = 0.003, respectively).

CONCLUSIONS

NF1 individuals have increased prevalence of macrocephaly, short stature, low BMI, and reduced abdominal fat. There is no relation between head circumference and anthropometric data with family history, or neurofibromas.

Propranolol Specifically Suppresses the Viability of Tumorous Schwann Cells Derived from Plexiform Neurofibromas In Vitro

BACKGROUND/AIM

Plexiform neurofibromas (PNFs) are benign tumors of the periph eral nerves sheath, which can damage neighboring organs, impair functions, cause pain and serious maxillofacial disfigurement, and have a high risk of malignant transformation. Complete resection is usually not possible since PNFs often extend through multiple layers of tissue. Therefore, it is necessary and beneficial to find a reasonable drug treatment for PNFs. Propranolol-treatment is the first-line therapy for infantile hemangiomas and the side effects are reversible and mostly benign. The present study aimed to examine the possible effect of propranolol for suppressing PNFs in vitro.

MATERIALS AND METHODS

Paired primary Schwann-cell-rich cultures and fibroblast-rich cultures were obtained from 4 PNFs of unrelated patients. Human Schwann cells (HSCs) were used as the control. These cultures were treated with propranolol for 7 days at concentrations up to 150 μM. Cells were then measured for their viability and immune-stained with S100 to label the tumorous Schwann cells.

RESULTS

Propranolol inhibited the viability of the tumorous Schwann cells in a dose-dependent manner, while did not substantially suppress viability of the non-tumorous fibroblasts derived from the same PNFs.

CONCLUSION

Propranolol may provide a treatment option for suppressing the growth of PNFs.

Partial empty sella syndrome, GH deficiency and transient central adrenal insufficiency in a patient with NF1

PURPOSE

To describe the case of a 9-year-old male patient with neurofibromatosis type 1 (NF1), partial empty sella (PES), transient central adrenal insufficiency (CAI) and growth hormone (GH) deficiency (GHD) treated with recombinant GH (rGH).

METHODS

The diagnosis of GHD was established upon peak GH response <10 ng/mL following glucagon and clonidine stimulation tests. CAI was diagnosed when peak cortisol response was <18 μg/dL following 1 μg Synacthen test (ST) with normal ACTH levels.

RESULTS

The diagnosis of NF1 was made at the age of 1.5 year. The patient first attended our Department at the age of 4.5 years. He presented with short stature (height: 95 cm < 3rd percentile), macrocephaly, frontal bossing, café-au-lait spots and bilateral proptosis. His growth rate (GR) initially was 5.3 cm/year. Brain/pituitary MRI showed T2-hyperintensities typical for NF1 and PES with reduced pituitary gland height (3 mm). The pituitary function tests revealed GHD. During follow-up his imaging findings remained unchanged, while his GR decelerated. He was started on rGH at the age of 8.5 years. Within the following year he grew 8.7 cm in height and could preserve a normal GR thereafter. At the age of 10.3 years, he was diagnosed with CAI (maximum cortisol response post-1 μg ST: 13.1 μg/dL). Ηe received hydrocortisone for 1 year. A repeat 1 μg ST off hydrocortisone showed normal cortisol response. During follow-up, brain MRI findings remained stable, while his pituitary demonstrated normal size and signal intensity.

CONCLUSION

Empty sella and hypopituitarism may occur in the context of NF1. Short stature may be associated with GHD in the absence of intrasellar masses in affected individuals. Lifelong endocrine follow-up is recommended for all NF1 patients.

Management of cutaneous neurofibroma: current therapy and future directions

Neurofibromatosis type 1 (NF1) is a life-long neurocutaneous disorder characterized by a predisposition to tumor development, including cutaneous neurofibroma (cNF), the hallmark of the disease. cNF is a histologically benign, multicellular tumor formed in virtually most individuals with NF1. It is considered the most burdensome feature of the disorder due to their physical discomfort, cosmetically disfiguring appearance, and psychosocial burden. Management of cNF remains a challenge in the medical field. Effective medicinal treatment for cNF does not exist at this time. Trials aimed at targeting individual components of the neoplasm such as mast cells with Ketotifen have not shown much success. Physical removal or destruction has been the mainstay of therapy. Surgical removal gives excellent cosmetic results, but risk in general anesthesia may require trained specialists. Destructive laser such as CO2 laser is effective in treating hundreds of tumors at one time but has high risk of scarring hypopigmentation or hyperpigmentation that alter cosmetic outcomes. A robust, low-risk surgical technique has been developed, which may be performed in clinic using traditional biopsy tools that may be more accessible to NF1 patients worldwide than contemporary techniques including Er:YAG or Nd:YAG laser. In this review, specific recommendations for management of cNFs are made based on symptoms, clinical expertise, and available resources. Additionally, antiproliferative agents aimed at stimulating cellular quiescence are explored.

Neurofibromatosis 1 French national guidelines based on an extensive literature review since 1966

Neurofibromatosis type 1 is a relatively common genetic disease, with a prevalence ranging between 1/3000 and 1/6000 people worldwide. The disease affects multiple systems with cutaneous, neurologic, and orthopedic as major manifestations which lead to significant morbidity or mortality. Indeed, NF1 patients are at an increased risk of malignancy and have a life expectancy about 10-15 years shorter than the general population. The mainstay of management of NF1 is a patient-centered longitudinal care with age-specific monitoring of clinical manifestations, aiming at the early recognition and symptomatic treatment of complications as they occur. Protocole national de diagnostic et de soins (PNDS) are mandatory French clinical practice guidelines for rare diseases required by the French national plan for rare diseases. Their purpose is to provide health care professionals with guidance regarding the optimal diagnostic and therapeutic management of patients affected with a rare disease; and thus, harmonizing their management nationwide. PNDS are usually developed through a critical literature review and a multidisciplinary expert consensus. The purpose of this article is to present the French guidelines on NF1, making them even more available to the international medical community. We further dwelled on the emerging new evidence that might have therapeutic potential or a strong impact on NF1 management in the coming feature. Given the complexity of the disease, the management of children and adults with NF1 entails the full complement healthcare providers and communication among the various specialties.

Growth Disturbances in Childhood Cancer Survivors

Survival from childhood cancer has improved dramatically over the last few decades, resulting in an increased need to address the long-term follow-up and care of childhood cancer survivors. Appropriate linear growth is an important measure of health, with alterations of growth in children and short adult height in those who have completed growth serving as potential indicators of the sequelae of the underlying diagnosis or the cancer treatments. It is therefore critical that clinicians, particularly endocrinologists, be familiar with the patterns of altered growth which may be seen following diagnosis and treatment for childhood cancer. In this article, we will review the growth alterations seen in childhood cancer survivors, focusing on risk factors and considerations in evaluation and care.

Receptor of ghrelin is expressed in cutaneous neurofibromas of individuals with neurofibromatosis 1

BACKGROUND

Multiple cutaneous neurofibromas are a hallmark of neurofibromatosis 1 (NF1). They begin to appear during puberty and increase in number and volume during pregnancy, suggesting a hormonal influence. Ghrelin is a hormone that acts via growth hormone secretagogue receptor (GHS-R), which is overexpressed in many neoplasms and is involved in tumorigenesis. We aimed to investigate GHS-R expression in NF1 cutaneous neurofibromas and its relationship with tumors volume, and patient's age and gender.

RESULTS

Sample comprised 108 cutaneous neurofibromas (55 large and 53 small tumors) from 55 NF1 individuals. GHS-R expression was investigated by immunohistochemistry in tissue micro and macroarrays and quantified using a digital computer-assisted method. All neurofibromas expressed GHS-R, with a percentage of positive cells ranging from 4.9% to 76.1%. Large neurofibromas expressed more GHS-R than the small ones. The percentage of GHS-R-positive cells and intensity of GHS-R expression were positively correlated with neurofibromas volume. GHS-R expression was more common in female gender.

CONCLUSIONS

GHS-R is expressed in cutaneous neurofibromas. Larger neurofibromas have a higher percentage of positive cells and higher GHS-R intensity. Based on our results we speculate that ghrelin may have an action on the tumorigenesis of cutaneous neurofibromas. Future studies are required to understand the role of ghrelin in the pathogenesis of NF1-associated cutaneous neurofibroma.

Rare Presentation of Neurofibromatosis and Turner Syndrome in a Pediatric Patient

Neurofibromatosis type 1 (NF1) is classically defined by the presence of multiple café-au-lait macules as one of the diagnostic criteria. Turner syndrome (TS) can also present with café-au-lait macules along with short stature. Our patient is the fifth reported with both NF1 and TS and the first who has been on growth hormone for short stature associated with TS.

Growth hormone excess in children with neurofibromatosis type-1 and optic glioma

In children with neurofibromatosis type 1 (NF1) and optic pathways glioma (OPG), growth hormone (GH) excess has been rarely reported and mainly associated to central precocious puberty. The aim of our study is to evaluate the prevalence of GH excess, the association with central precocious puberty, the relation with tumor site and the evolution over time in a large cohort of children with NF1 and OPG. Sixty-four NF1 children with OPG were evaluated. Patients with stature and/or height velocity >2 SD for age were studied for GH secretion. Seven out of 64 children (10.9%) with NF1 and optic pathways glioma showed GH excess, isolated in 5 cases and associated to central precocious puberty in 2. All the children with GH excess had a tumor involving the chiasma. Children with GH excess underwent medical treatment with lanreotide and a minimum clinical/biochemical follow up of 2 years is reported. The present study demonstrates that GH excess should be considered as a relative frequent endocrine manifestation in NF1 patients, similarly to central precocious puberty. Therefore, these patients should undergo frequent accurate auxologic evaluations. On the other hand, an increase in height velocity in children with NF1, even despite normal ophthalmological exams, can suggest the presence of OPG and therefore represents an indication to perform brain MRI.

Initial Exploration on Temporal Branch of Facial Nerve Function Preservation in Plexiform Neurofibroma Resection

Background:

Large temporal plexiform neurofibroma (PNF) is an irritating problem that causes facial disfigurement. Surgical resection of PNF is the only effective way to remove the tumor as well as to improve the patient's facial appearance. However, temporal branch of the facial nerve (TBFN) in the tumor is prone to be destroyed during PNF removal. Thus, TBFN palsy is the inevitable complication after surgery and might induce other malformation and dysfunction. Therefore, the aim of this study is to reconstruct a nearly normal face contour while preserving the facial nerve function.

Purpose:

Selective PNF removal technique was designed to protect TBFN during PNF lesions resection in our patients.

Methods:

From May 2011 to June 2015, the authors had 10 patients who suffered from PNF in the temporal region with facial disfigurement and underwent selective PNF removal to correct the facial disfigurement while preserving TBFN as well.

Result:

All patients obtained the improvement of facial appearance after surgery. The temporal PNF was removed and the TBFN function successfully maintained. Plexiform neurofibroma recurrence has not been relapsed during 6 to 49 months’ follow-up.

Conclusions:

In our initial exploration, TBFN function maintenance and facial appearance improvement can be achieved simultaneously by using PNF-selective removal surgery technique.

Endocrine implications of neurofibromatosis 1 in childhood

In 1882, von Recklinghausen described a group of patients with multiple tumors arising from the 'endoneurium' of peripheral nerves, and called them 'neurofibromas'. The term von Recklinghausen disease was used up to the end of the 20th century, when the gene of neurofibromatosis (NF1) was cloned on chromosome 17q11.2. The gene product is a cytoplasmic protein termed neurofibromin, regulating proliferation and maturation of both glial and neuronal progenitors during embryogenesis. Loss of neurofibromin function determines the hyperactivation of the proto-oncogene RAS, leading to an increased risk of tumor formation, predominantly affecting the skin, bone and the nervous system. NF1 is clinically and genetically distinct from neurofibromatosis type 2, characterized by bilateral vestibular schwannomas and other nervous system tumors. An increased incidence of central precocious puberty, diencephalic syndrome, GH deficiency and GH hypersecretion has been described in NF1 children. These conditions are commonly complications of optic pathway gliomas (OPG) involving the hypothalamic and sellar region. Nevertheless, these endocrine disorders have been observed also in children without evidence of OPG at magnetic resonance imaging. Clinical and laboratory follow-up is crucial in all children with NF1, particularly in those with an OPG, aiming at the early identification of signs suggestive of secondary endocrine alterations.

Risk of Neoplasia in Pediatric Patients Receiving Growth Hormone Therapy--A Report From the Pediatric Endocrine Society Drug and Therapeutics Committee

CONTEXT

GH and IGF-1 have been shown to affect tumor growth in vitro and in some animal models. This report summarizes the available evidence on whether GH therapy in childhood is associated with an increased risk of neoplasia during treatment or after treatment is completed.

EVIDENCE ACQUISITION

A PubMed search conducted through February 2014 retrieved original articles written in English addressing GH therapy and neoplasia risk. Subsequent searches were done to include additional relevant publications.

EVIDENCE SYNTHESIS

In children without prior cancer or known risk factors for developing cancer, the clinical evidence does not affirm an association between GH therapy during childhood and neoplasia. GH therapy has not been reported to increase the risk for neoplasia in this population, although most of these data are derived from postmarketing surveillance studies lacking rigorous controls. In patients who are at higher risk for developing cancer, current evidence is insufficient to conclude whether or not GH further increases cancer risk. GH treatment of pediatric cancer survivors does not appear to increase the risk of recurrence but may increase their risk for subsequent primary neoplasms.

CONCLUSIONS

In children without known risk factors for malignancy, GH therapy can be safely administered without concerns about an increased risk for neoplasia. GH use in children with medical diagnoses predisposing them to the development of malignancies should be critically analyzed on an individual basis, and if chosen, appropriate surveillance for malignancies should be undertaken. GH can be used to treat GH-deficient childhood cancer survivors who are in remission with the understanding that GH therapy may increase their risk for second neoplasms.

Validity and interexaminer reliability of a new method to quantify skin neurofibromas of neurofibromatosis 1 using paper frames

BACKGROUND

Skin neurofibromas represent one of the main clinical manifestations of neurofibromatosis 1, and their number varies greatly between individuals. Quantifying their number is an important step in the methodology of many clinical studies, but counting neurofibromas one by one in individuals with thousands of tumors is arduous, time-consuming, and subject to intra and interexaminer variability. We aimed to evaluate the efficacy of a new methodology for skin neurofibromas quantification using paper frames.

METHODS

The sample comprised 92 individuals with NF1. Paper frames, with a central square measuring 100 cm2, were placed on the back, abdomen and thigh. Images were taken, transferred to a computer and two independent examiners counted the neurofibromas. The average number of neurofibromas/100 cm2 of skin was obtained from the mean of the three values. The differences in the quantity of neurofibromas counted by two examiners were evaluated with Intraclass correlation coefficient (ICC), paired t-test, Bland-Altman and survival-agreement plots. To evaluate the predictive value of the method in obtaining the total number of neurofibromas, 49 participants also had their tumors counted one by one. Reproducibility was assessed with Pearson's correlation coefficients and simple linear regression model.

RESULTS

There was excellent agreement between examiners (ICC range 0.992-0.997) and the total number of skin neurofibromas could be predicted by the adhesive frames technique using a specific formula (P < 0.0001).

CONCLUSIONS

In this article we describe a reliable, easy and rapid technique using paper frames to quantify skin neurofibromas that accurately predicts the total number of these tumors in patients with NF1. This method may be a useful tool in clinical practice and clinical research to help achieve an accurate quantitative phenotype of NF1.

Nilotinib is more potent than imatinib for treating plexiform neurofibroma in vitro and in vivo

Plexiform neurofibromas (PNFs) are benign nerve sheath tumors mostly associated with neurofibromatosis type 1. They often extend through multiple layers of tissue and therefore cannot be treated satisfactorily by surgery. Nilotinib is a tyrosine kinase inhibitor used to treat leukemia, with advantages over the prototype imatinib in terms of potency and selectivity towards BCR-ABL, and the DDR, PDGFR, and KIT receptor kinases. In this study, we compared efficacies of the two drugs on cultured cells of PNF in vitro and on xenografted tumor fragments on sciatic nerve of athymic nude mice. Xenografts were monitored weekly using a high resolution ultrasound measurement. Treatment with nilotinib at a daily dose of 100 mg/kg for four weeks led to a reduction of the graft sizes_std by 68_±7% in the 8 treated mice, significantly more than the 33_±8% reduction in the 8 untreated mice (P<0.05) and the 47_±15% in the 7 mice treated with imatinib (P<0.05). The peak plasma nilotinib concentration 6.6_±1.1 µM is within the pharmacological range of clinical application. Imatinib, but not nilotinib significantly hindered body weight increase of the mice and elevated cytotoxicity of mouse spleen cells (P<0.05). Our results suggest that nilotinib may be more potent than imatinib for treating PNFs and may also be better tolerated. Imatinib seems to have some off-target effect in elevating immunity.

Evaluation of Bcl-2, Bcl-x and Cleaved Caspase-3 in Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

AIMS: To study the expression of Bcl-2, Bcl-x, as well the presence of cleaved caspase-3 in neurofibromas and malignant peripheral nerve sheath tumors. The expression of Bcl-2 and Bcl-x and the presence of cleaved caspase 3 were compared to clinicopathological features of malignant peripheral nerve sheath tumors and their impact on survival rates were also investigated. MATERIALS AND METHODS: The evaluation of Bcl-2, Bcl-x and cleaved caspase-3 was performed by immunohistochemistry using tissue microarrays in 28 malignant peripheral nerve sheath tumors and 38 neurofibromas. Immunoquantification was performed by computerized digital image analysis. CONCLUSIONS: Apoptosis is altered in neurofibromas and mainly in malignant peripheral nerve sheath tumors. High levels of cleaved caspase-3 are more common in tumors with more aggressive histological features and it is associated with lower disease free survival of patients with malignant peripheral nerve sheath tumors.

Analysis of steroid hormone effects on xenografted human NF1 tumor schwann cells

The neurofibroma, a common feature of neurofibromatosis type 1 (NF1), is a benign peripheral nerve sheath tumor that contains predominantly Schwann cells (SC). There are reports that neurofibroma growth may be affected by hormonal changes, particularly in puberty and pregnancy, suggesting an influence by steroid hormones. This study examined the effects of estrogen and progesterone on proliferation and apoptosis in a panel of NF1 tumor xenografts. SC-enriched cultures derived from three human NF1 tumor types (dermal neurofibroma, plexiform neurofibroma, and malignant peripheral nerve sheath tumor (MPNST)) were xenografted in sciatic nerves of ovariectomized scid /Nf1-/+ mice. At the same time, mice were implanted with time-release pellets for systemic delivery of progesterone, estrogen or placebo. Proliferation and apoptosis by the xenografted SC were examined two months after implantation, by Ki67 immunolabeling and TUNEL. Estrogen was found to increase the growth of all three MPNST xenografts. Progesterone was associated with increased growth in two of the three MPNSTs, yet decreased growth of the other. Of the four dermal neurofibroma xenografts tested, estrogen caused a statistically significant growth increase in one, and progesterone did in another. Of the four plexiform neurofibroma SC xenografts, estrogen and progesterone significantly decreased growth in one of the xenografts, but not the other three. No relationship of patient age or gender to steroid response was observed. These findings indicate that human NF1 Schwann cells derived from some tumors show increased proliferation or decreased apoptosis in response to particular steroid hormones in a mouse xenograft model. This suggests that anti-estrogen or anti-progesterone therapies may be worth considering for specific NF1 neurofibromas and MPNSTs.

Neurofibromatosis with unilateral lower limb gigantism

The case of a 3-year-old child diagnosed with Type 1 neurofibromatosis is presented, showing pigmented birthmarks and gigantism of the left lower limb associated with the presence of multiple neurofibromas. Increased bone growth appears to be the direct or indirect consequence of a still undefined paracrine effect of nerve tumor cells.