Glomus tumors in neurofibromatosis type 1: genetic, functional, and clinical evidence of a novel association

Macrocephaly and Finger Changes: A Narrative Review

Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals.

En Bloc Excision and Bone Grafting for Monostotic Multiple Intraosseous Glomus Tumors of the Distal Phalanx: A Case Report

CASE

Glomus tumors of the hand are rare tumors that occur predominantly in the subungual region. Though multicentric glomus tumors have been reported in the subungual region involving the nailbed, monostotic multiple intraosseous glomus tumors have not been reported so far. We report a case of a 36 year-old woman who presented with a 5-year history of intermittent thumb pain, aggravated with exposure to cold or pressure. A glomus tumor of the thumb was excised, but symptoms returned 3 months later. She ultimately underwent curettage with bone grafting of a recurrent glomus tumor at the same site, and has been free of symptoms for 1.5 years.

CONCLUSION

Intraosseous glomus tumors may present as multiple synchronous lesions. This, to the best of our knowledge, is the first case report of monostotic multiple intraosseous glomus tumors.

A case of solitary digital glomus tumor associated with neurofibromatosis type 1

An association between glomus tumor and neurofibromatosis type 1 has been reported. It is characterized by multiple tumors and young age at onset. The early diagnosis of neurofibromatosis type 1 is important because it is associated with a high rate of malignancy. A 25-year-old man presented to our hospital with left index finger pain that had persisted for 6 years. Physical and imaging findings suggested a benign soft-tissue tumor. Surgery was performed, and the tumor was pathologically diagnosed as glomus tumor. In this case, the patient with a young-onset glomus tumor was suspected of having neurofibromatosis type 1. An additional medical examination led to the diagnosis of unrecognized neurofibromatosis type 1. We experienced a case in which the onset of a glomus tumor led to the diagnosis of neurofibromatosis type 1. Comorbid neurofibromatosis type 1 should be kept in mind when glomus tumors are diagnosed.

Neurofibromatosis Type 1-Associated Optic Pathway Gliomas: Current Challenges and Future Prospects

Optic pathway glioma (OPG) occurs in as many as one-fifth of individuals with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome. Generally considered low-grade and slow growing, many children with NF1-OPGs remain asymptomatic. However, due to their location within the optic pathway, ~20-30% of those harboring NF1-OPGs will experience symptoms, including progressive vision loss, proptosis, diplopia, and precocious puberty. While treatment with conventional chemotherapy is largely effective at attenuating tumor growth, it is not clear whether there is much long-term recovery of visual function. Additionally, because these tumors predominantly affect young children, there are unique challenges to NF1-OPG diagnosis, monitoring, and longitudinal management. Over the past two decades, the employment of authenticated genetically engineered Nf1-OPG mouse models have provided key insights into the function of the NF1 protein, neurofibromin, as well as the molecular and cellular pathways that contribute to optic gliomagenesis. Findings from these studies have resulted in the identification of new molecular targets whose inhibition blocks murine Nf1-OPG growth in preclinical studies. Some of these promising compounds have now entered into early clinical trials. Future research focused on defining the determinants that underlie optic glioma initiation, expansion, and tumor-induced optic nerve injury will pave the way to personalized risk assessment strategies, improved tumor monitoring, and optimized treatment plans for children with NF1-OPG.

Dermatologic Manifestations of Neurofibromatosis Type 1 and Emerging Treatments

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that increases one's risk for both benign and malignant tumors. NF1 affects every organ in the body, but the most distinctive symptoms that are often the most bothersome to patients are the cutaneous manifestations, which can be unsightly, cause pain or pruritus, and have limited therapeutic options. In an effort to increase awareness of lesser-known dermatologic associations and to promote multidisciplinary care, we conducted a narrative review to shed light on dermatologic associations of NF1 as well as emerging treatment options. Topics covered include cutaneous neurofibromas, plexiform neurofibromas, diffuse neurofibromas, distinct nodular lesions, malignant peripheral nerve sheath tumors, glomus tumors, juvenile xanthogranulomas, skin cancer, and cutaneous T-cell lymphoma.

Glomus Tumor Within the Tensor Fascia Lata: A Case Report

BACKGROUND Glomus tumors are rare, benign, soft-tissue lesions, usually occurring in the hand, but they can occur in other regions of the body, such as the thigh. Most of the time, extradigital glomus tumors are difficult to diagnose, and symptoms can persist for a long time. The usual clinical presentations consist of pain, tenderness at the site of the tumor, and hypersensitivity to cold. CASE REPORT We report a case of a GT of the proximal thigh in a 39-year-old man with left thigh pain without palpable mass for several years, without clear diagnosis. He had pain and hyperesthesia exacerbated by running. The patient was diagnosed initially by ultrasound imaging, which revealed a round, solid, hypoechoic, homogeneous mass in the left upper thigh. Magnetic resonance imaging (MRI) with contrast showed a well-defined intramuscular lesion in the tensor fascia lata. A percutaneous biopsy was done through ultrasound guidance, followed by excisional biopsy and immediate pain relief. CONCLUSIONS Glomus tumors of the thigh are a rare neoplasm, especially in the proximal thigh; they are difficult to diagnose and are associated with morbidity. Diagnosis can be made through a systematic approach and simple investigation, such as via ultrasonography. A percutaneous biopsy can help in drawing up a management plan, and malignancy must be considered if the lesion is suspicious. Symptoms can persist in case of incomplete resection or unrecognized synchronous satellite lesions; thus, symptomatic neuroma should be considered.

Gastrointestinal Glomus Tumors: A Single Institution, 20-Year Retrospective Study

INTRODUCTION

Glomus tumors are rare mesenchymal neoplasms composed of cells resembling those of the thermoregulatory glomus body, typically occurring in the skin and superficial soft tissues. Rarely do they occur in the gastrointestinal tract, in particular the stomach, where they have been the subject of case reports and small series. We present our institutional experience with gastrointestinal glomus tumors.

METHODS

A retrospective review of all gastrointestinal glomus tumors was conducted across all three Mayo Clinic sites in Minnesota, Arizona, and Florida from 2001 to 2021. Patient characteristics, pathologic findings, imaging features, operative reports, and clinical outcomes were abstracted. Descriptive statistics were utilized to report outcomes.

RESULTS

Nine patients with glomus tumors were identified (five men and four women). The median age was 53 [interquartile range (IQR), 44-69] y. Four patients presented with abdominal discomfort, three had anemia or bleeding, and two tumors were incidentally diagnosed. Computed tomography scans identified masses thought to represent gastrointestinal stromal tumors or neuroendocrine tumors in all patients. The tumors were localized to the stomach in all cases, specifically in the gastric antrum. Seven patients underwent preoperative endoscopy, including five with endoscopic ultrasonography. Endoscopic biopsies were interpreted as glomus tumors (n = 3), neuroendocrine tumors (n = 2), and nondiagnostic (n = 2). All patients underwent open (n = 3) or minimally invasive (n = 6) margin-negative resection by wedge resection (n = 5) or distal gastrectomy (n = 4). No nodal metastases were identified radiographically or on pathologic examination. The median tumor size was 2.5 [IQR 1.3-3.4] cm. All tumors showed at least in part typical glomus tumor morphology and smooth muscle actin expression. Aberrant synaptophysin expression was present in the two tumors initially classified as NET. Using the current WHO criteria, tumors were classified as histologically malignant (n = 1) and of "uncertain malignant potential" (n = 8). At a median follow-up of 15 [IQR 1-56] mo, all patients were asymptomatic and without recurrence. Two patients died of unrelated causes. No patients received adjuvant therapies.

CONCLUSIONS

Our 20-year, single institution, 3-site experience with resected gastrointestinal glomus tumors suggests the rarity, predisposition to involve the gastric antrum, and potentially an indolent clinical behavior of many of these tumors. Long-term follow-up is warranted as some previously reported gastric glomus tumors have metastasized, including cases lacking morphologic evidence of malignancy. Surgical resection, with minimally invasive wedge resection alone, is likely sufficient for the management of most gastric glomus tumors.

Neurofibromatosis Type 1 and Hypospadias in a Male 46, XY with a Mutation in the NF1 Gene and a Mutation in NR5A1

Neurofibromatosis type 1 is one of the most common genetic autosomal dominant disorders described, with a prevalence of 1 in 2000 to 1 in 3000 individuals. It is characterized by skin, nerves, and bone abnormalities. Non-related to NF1, hypospadias is a displacement in the urethral opening which in the majority of patients has an idiopathic cause. Here, we describe a patient with neurofibromatosis type 1, hypospadias, and unilateral cryptorchidism. The heterozygous variants c.6789_6792delTTAC, p.(Tyr2264Thrfs*5) and c.140A>G, p.(Tyr47Cys) were found in the NF1 and NR5A1 genes, respectively. This case contributes to the phenotypical characterization of patients with NF1 but also with hypospadias caused by a mutation in the NR5A1 gene, which usually leads to severe sex disorders.

Glomus tumors around or in the knee: a case report and literature review

BACKGROUND

Glomus tumors commonly affect the extremities, especially subungual. And glomus tumors rarely occur around knee, which are often misdiagnosed. A lack of experience with glomus tumors is likely the cause.

CASE PRESENTATION

A 42-year-old female presented with continuous dull pain of right knee for the past 7 years. Severe pain was experienced after walking a few hundred meters or climbing up or down stairs. The patient had a slight limp, and the lateral superior aspect of her right knee was tender to palpation. The range of motion and skin around her right knee were normal. Magnetic resonance imaging revealed a well-defined abnormal lesion confluent with the periosteum on the femoral lateral supracondylar. She was finally diagnosed with glomus tumor according to pathological results. After surgery, the pain disappeared, and the patient was discharged three days postoperatively. At the 18-month follow-up visit, the patient reported sustained pain relief, and regular follow-ups were continued. Additionally, 30 published reports documenting 36 cases of glomus tumors around the knee were reviewed, which showed that 20% of all reported cases of glomus tumor around the knee had a history of trauma. The median age for male with glomus tumor was greater than that of female; however, the median duration of illness between the two groups was equivalent. The mean diameters of glomus tumors ranged from 4 to 65 mm, and locations around the knee included the knee joint cavity, soft tissue (e.g. popliteal fossa, patellar tendon, iliotibial band, and Hoffa's fat pad), distal femur, and proximal tibia.

CONCLUSION

Literature review demonstrated that no significant differences were found between male and female with glomus tumor in regard to location (left or right side) and illness duration. It was noting that a history of trauma may be a cause of glomus tumor and approximate 94.4% of glomus tumors was benign. The most effective therapy accepted for glomus tumors is complete surgical excision, and recurrence was rare after complete surgical excision.

The RASopathies: Biology, genetics and therapeutic options

The RASopathies are a group of genetic diseases in which the Ras/MAPK signaling pathway is inappropriately activated as a result of mutations in genes encoding proteins within this pathway. As their causative mutations have been identified, this group of diseases has expanded to include neurofibromatosis type 1 (NF1), Legius syndrome, Noonan syndrome, CBL syndrome, Noonan syndrome-like disorder with loose anagen hair, Noonan syndrome with multiple lentigines, Costello syndrome, cardiofaciocutaneous syndrome, gingival fibromatosis and capillary malformation-arteriovenous malformation syndrome. Many of these genetic disorders share clinical features in common such as abnormal facies, short stature, varying degrees of cognitive impairment, cardiovascular abnormalities, skeletal abnormalities and a predisposition to develop benign and malignant neoplasms. Others are more dissimilar, even though their mutations are in the same gene that is mutated in a different RASopathy. Here, we describe the clinical features of each RASopathy and contrast them with the other RASopathies. We discuss the genetics of these disorders, including the causative mutations for each RASopathy, the impact that these mutations have on the function of an individual protein and how this dysregulates the Ras/MAPK signaling pathway. As several of these individual disorders are genetically heterogeneous, we also consider the different genes that can be mutated to produce disease with the same phenotype. We also discuss how our growing understanding of dysregulated Ras/MAPK signaling had led to the development of new therapeutic agents and what work will be critically important in the future to improve the lives of patients with RASopathies.

Diagnosis of glomus tumor of the elbow: A case report

INTRODUCTION

Glomus tumors are rare and often benign vascular lesions that present classically in the subungual region of the hand. Nonetheless, presentations in atypical sites have been reported over the years. However, the classic symptoms of typical glomus tumors are often absent in tumors of atypical sites.

CASE PRESENTATION

We present a case of an extradigital glomus tumor with a 3-year history of pain in the lateral aspect of the elbow.

DISCUSSION

The case we present took three years and multiple visits to different clinics and specialties to reach the final diagnosis and management. It often takes longer to diagnose Glomus tumors of atypical sites and presentations. The causes could be related to the rare incidence, the atypical presentation in site and symptoms, or the diagnostic methods.

CONCLUSION

This case report discusses the possible causes behind the diagnostic delay in extradigital glomus tumors, aiming to raise clinical awareness among primary health care physicians.

Neurofibromatoses

The neurofibromatoses are a group of genetic disorders that cause development of nervous system tumors as well as various other tumor and systemic manifestations. Neurofibromatosis type 1 is the most prevalent of these conditions and has the most variable phenotype and highest risk of malignant tumor formation. Neurofibromatosis type 2 has no associated malignant tumors but does carry significant morbidity, including deafness, facial weakness, and physical disability. Schwannomatosis is the least prevalent of these disorders and is characterized primarily by nonvestibular schwannomas and pain.

CARMN-NOTCH2 fusion transcript drives high NOTCH2 expression in glomus tumors of the upper digestive tract

Glomus tumors (GTs) are perivascular tumors mostly occurring in the distal extremities. Rare cases arise in the digestive tract and may be misdiagnosed with neuroendocrine or gastrointestinal stromal tumors. We aimed to specify the features of GT of the upper digestive tract. Clinical, histological, phenotypic, and molecular features of 16 digestive GTs were analyzed, of whom two underwent whole exome and RNA sequencing to search for gene alterations. RNA-sequencing disclosed a t(1:5)(p13;q32) translocation, which resulted in the fusion of CARMN and NOTCH2 in two GTs. The fusion gene encoded a protein sequence corresponding to the NOTCH2 intracellular domain that functions as transcription factor. These finding was supported by high expression of genes targeted by NOTCH. The CARMN-NOTCH2 translocation was detected in 14 out of 16 (88%) GTs of the upper digestive tract; but in only in two out of six cutaneous GTs (33%). Most digestive GT arose from the stomach (n = 13), and the others from duodenal (2) or oesophagous (1). Nuclear expression of NOTCH2 was detected in the 14 cases containing the fusion transcripts. The CARMN-NOTCH2 fusion transcript may contribute to activation of the NOTCH2 pathway in GT and drive tumor development. The high frequency of this translocation in GT of the upper digestive track suggest that detection of nuclear NOTCH2 expression may be useful diagnostic biomarker of these tumors.

Cutaneous Findings in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a complex autosomal dominant disorder associated with germline mutations in the NF1 tumor suppressor gene. NF1 belongs to a class of congenital anomaly syndromes called RASopathies, a group of rare genetic conditions caused by mutations in the Ras/mitogen-activated protein kinase pathway. Generally, NF1 patients present with dermatologic manifestations. In this review the main features of café-au-lait macules, freckling, neurofibromas, juvenile xanthogranuloma, nevus anemicus and other cutaneous findings will be discussed.

Peripheral nerve tumors of the hand: Clinical features, diagnosis, and treatment

The majority of the tumors arising from the peripheral nerves of the hand are relatively benign. However, a tumor diagnosed as malignant peripheral nerve sheath tumor (MPNST) has destructive consequences. Clinical signs and symptoms are usually caused by direct and indirect effects of the tumor, such as nerve invasion or compression and infiltration of surrounding tissues. Definitive diagnosis is made by tumor biopsy. Complete surgical removal with maximum reservation of residual neurologic function is the most appropriate intervention for most symptomatic benign peripheral nerve tumors (PNTs) of the hand; however, MPNSTs require surgical resection with a sufficiently wide margin or even amputation to improve prognosis. In this article, we review the clinical presentation and radiographic features, summarize the evidence for an accurate diagnosis, and discuss the available treatment options for PNTs of the hand.

Primary glomus tumour of the pituitary gland: diagnostic challenges of a rare and potentially aggressive neoplasm

Primary non-neuroendocrine tumours of the pituitary gland and sella are rare lesions often challenging to diagnose. We describe two cases of clinically aggressive primary glomus tumour of the pituitary gland. The lesions occurred in a 63-year-old male and a 30-year-old female who presented with headache, blurred vision and hypopituitarism. Neuroimaging demonstrated large sellar and suprasellar tumours invading the surrounding structures. Histologically, the lesions were characterised by angiocentric sheets and nests of atypical cells that expressed vimentin, smooth muscle actin and CD34. Perivascular deposition of collagen IV was also a feature. Case 2 expressed synaptophysin. INI-1 (SMARCB1) expression was preserved. Both lesions were mitotically active and demonstrated a Ki-67 labelling index of 30%. Next-generation sequencing performed in case 1 showed no mutations in the reading frame of 37 commonly mutated oncogenes, including BRAF and KRAS. Four pituitary glomus tumours have previously been reported, none of which showed features of malignant glomus tumour. Similar to our two patients, three previous examples displayed aggressive behaviour.

Genome-wide association study of café-au-lait macule number in neurofibromatosis type 1

Background

Neurofibromatosis type 1 (NF1) is a tumor‐predisposition disorder that arises due to pathogenic variants in tumor suppressor NF1. NF1 has variable expressivity that may be due, at least in part, from heritable elements such as modifier genes; however, few genetic modifiers have been identified to date.

Methods

In this study, we performed a genome‐wide association analysis of the number of café‐au‐lait macules (CALM) that are considered a tumor‐like trait as a clinical phenotype modifying NF1.

Results

A borderline genome‐wide significant association was identified in the discovery cohort (CALM1, N = 112) between CALM number and rs12190451 (and rs3799603, r² = 1.0; p = 7.4 × 10⁻⁸) in the intronic region of RPS6KA2. Although, this association was not replicated in the second cohort (CALM2, N = 59) and a meta‐analysis did not show significantly associated variants in this region, a significant corroboration score (0.72) was obtained for the RPS6KA2 signal in the discovery cohort (CALM1) using Complementary Pairs Stability Selection for Genome‐Wide Association Studies (ComPaSS‐GWAS) analysis, suggesting that the lack of replication may be due to heterogeneity of the cohorts rather than type I error.

Conclusion

rs12190451 is located in a melanocyte‐specific enhancer and may influence RPS6KA2 expression in melanocytes—warranting further functional studies.

Fibroblast‑derived exosomal microRNA‑369 potentiates migration and invasion of lung squamous cell carcinoma cells via NF1‑mediated MAPK signaling pathway

Cancer-associated fibroblasts (CAFs) exhibit tumor-stimulating properties and are associated with poor survival in several types of cancer, making them potential therapeutic targets. The present study aimed to determine whether CAFs were associated with cell migration and invasion in lung squamous cell carcinoma (LUSC), as well as their association with microRNA-369 (miR-369) in these processes. Firstly, the changes of the malignant biological behavior were observed by treating the LUSC cells with the CAFs-derived extracellular vesicles (CAFs-EVs). Subsequently, the differentially expressed miRNAs in the cells treated with CAFs-EVs were analyzed by microarray analysis. Following inhibition of miR-369 expression in CAFs-EVs, LUSC cells were co-cultured, and the malignant biological behavior of the cells was re-examined. Then, through bioinformatics analysis and verification, the mRNA targets of miR-369 and the corresponding downstream signaling pathway were screened out. Finally, the effects of CAFs-EVs on the growth and metastasis of LUSC were demonstrated by in vivo tumor formation and metastasis experiments. It was identified that miR-369 was expressed at a relatively high level in the CAFs-EVs. Neurofibromin-1 (NF1) was hypothesized as a direct target of miR-369 in LUSC. Also, the overexpression of miR-369 activated the mitogen-activated protein kinase signaling pathway by interacting with NF1, consequently potentiating LUSC cell growth. The present study provided novel insights into the action of miR-369 in CAFs-EVs in controlling LUSC cell migration, invasion and tumorigenesis, and identified miR-369 in CAFs-EVs as an important prognostic marker and therapeutic target.

Phakomatoses

Phakomatoses present with characteristic findings on the skin, central or peripheral nervous system, and tumors. Neurofibromatosis type 1 is the most common syndrome and is characterized by Café-au-lait macules, intertriginous freckling, Lisch nodules, and tumors including neurofibromas, malignant peripheral nerve sheath tumors, and gliomas. Tuberous Sclerosis Complex is characterized by benign hamartomas presenting with hypomelanotic macules, shagreen patches, angiofibromas, confetti lesions and tumors including cortical tubers, subependymal nodules, subependymal giant cell astrocytomas and tumors of the kidney, lung, and heart. Managing these disorders requires disease specific supportive care, tumor monitoring, surveillance for selected cancers, and treatment of comorbid conditions.

Painful Vater-Pacini neuroma of the digit in neurofibromatosis type 1

Vater-Pacini neuromas are rare causes of severe pain in the phalanges. The cause of this change in the tactile corpuscles is unknown. A traumatic cause has been plausibly demonstrated, at least in some cases. Here, the rare occurrence of a Vater-Pacini neuroma in a patient with neurofibromatosis type 1 is reported. The discussion addresses the difficulties of terminology and current diagnostic procedures for differentiating small nodular masses of the palm and digits. The surgical treatment leads to rapid relief of the symptoms.

Painful tumors in a patient with neurofibromatosis type 1: a case report

BACKGROUND

Herein, we report an unusual case of multifocal glomus tumors in the same hand in a patient suffering from neurofibromatosis type 1.

CASE PRESENTATION

The patient was a 37-year-old Moroccan woman, suffering from neurofibromatosis type 1, with intense pain in the fingers, successfully treated with the excision of the tumors. Histology of the lesions confirmed the diagnosis of glomus tumor.

CONCLUSION

We present this case to support the association between glomus tumors and neurofibromatosis type 1. Thus, we strongly recommend that one should suspect a glomus tumor in patients with neurofibromatosis type 1 if such patients have symptoms from finger pulp or nails.

Recent Advances in the Diagnosis and Pathogenesis of Neurofibromatosis Type 1 (NF1)-associated Peripheral Nervous System Neoplasms

The diagnosis of a neurofibroma or a malignant peripheral nerve sheath tumor (MPNST) often raises the question of whether the patient has the genetic disorder neurofibromatosis type 1 (NF1) as well as how this will impact the patient's outcome, what their risk is for developing additional neoplasms and whether treatment options differ for NF1-associated and sporadic peripheral nerve sheath tumors. Establishing a diagnosis of NF1 is challenging as this disorder has numerous neoplastic and non-neoplastic manifestations which are variably present in individual patients. Further, other genetic diseases affecting the Ras signaling cascade (RASopathies) mimic many of the clinical features of NF1. Here, we review the clinical manifestations of NF1 and compare and contrast them with those of the RASopathies. We also consider current approaches to genetic testing for germline NF1 mutations. We then focus on NF1-associated neurofibromas, considering first the complicated clinical behavior and pathology of these neoplasms and then discussing our current understanding of the genomic abnormalities that drive their pathogenesis, including the mutations encountered in atypical neurofibromas. As several neurofibroma subtypes are capable of undergoing malignant transformation to become MPNSTs, we compare and contrast patient outcomes in sporadic, NF1-associated and radiation-induced MPNSTs, and review the challenging pathology of these lesions. The mutations involved in neurofibroma-MPNST progression, including the recent identification of mutations affecting epigenetic regulators, are then considered. Finally, we explore how our current understanding of neurofibroma and MPNST pathogenesis is informing the design of new therapies for these neoplasms.

Insights into optic pathway glioma vision loss from mouse models of neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a common cancer predisposition syndrome caused by mutations in the NF1 gene. The NF1-encoded protein (neurofibromin) is an inhibitor of the oncoprotein RAS and controls cell growth and survival. Individuals with NF1 are prone to developing low-grade tumors of the optic nerves, chiasm, tracts, and radiations, termed optic pathway gliomas (OPGs), which can cause vision loss. A paucity of surgical tumor specimens and of patient-derived xenografts for investigative studies has limited our understanding of human NF1-associated OPG (NF1-OPG). However, mice genetically engineered to harbor Nf1 gene mutations develop optic gliomas that share many features of their human counterparts. These genetically engineered mouse (GEM) strains have provided important insights into the cellular and molecular determinants that underlie mouse Nf1 optic glioma development, maintenance, and associated vision loss, with relevance by extension to human NF1-OPG disease. Herein, we review our current understanding of NF1-OPG pathobiology and describe the mechanisms responsible for tumor initiation, growth, and associated vision loss in Nf1 GEM models. We also discuss how Nf1 GEM and other preclinical models can be deployed to identify and evaluate molecularly targeted therapies for OPG, particularly as they pertain to future strategies aimed at preventing or improving tumor-associated vision loss in children with NF1.

Glomangiomyoma of the Vagina: A Report of 2 Cases and Literature Review

We report 2 cases of vaginal glomangiomyoma in a 53-year-old who presented with a painful vaginal mass, and a 56-year-old who had postmenopausal bleeding and in whom an incidental vaginal mass was identified and resected at the time of hysterectomy. Histologic examination of the resected masses showed solid, circumscribed, benign, smooth muscle-predominant tumors with interspersed small islands of epithelioid glomus cells. The glomus cells were intimately related to small-caliber blood vessels and showed no cytologic atypia or mitotic activity. The tumor cells showed diffuse expression of smooth muscle actin, CD34, and focal expression of h-caldesmon, vimentin, and estrogen receptor. No immunolabeling for calponin B or desmin was found. To our knowledge, there are only isolated reports of vaginal glomus tumors, and these are the first reported case of vaginal glomangiomyoma in the literature.

Combinatorial therapeutic targeting of BMP2 and MEK-ERK pathways in NF1-associated malignant peripheral nerve sheath tumors

The clinical management of malignant peripheral nerve sheath tumors (MPNSTs) is challenging not only due to its aggressive and invasive nature, but also limited therapeutic options. Using gene expression profiling, our lab identified BMP2-SMAD1/5/8 pathway as a potential therapeutic target for treating MPNSTs. In this study, we explored the therapeutic impact of targeting BMP2-SMAD1/5/8 pathway in conjunction with RAS-MEK-ERK signaling, which is constitutively activated in MPNSTs. Our results indicated that single agent treatment with LDN-193189, a BMP2 Type I receptor inhibitor, did not affect the growth and survival of MPNST cells at biochemically relevant inhibitory concentrations. However, addition of a MEK1/2 inhibitor, selumetinib, to LDN-193189-treated cells resulted in significant inhibition of cell growth and induction of cell death. LDN-193189 at biochemically effective concentrations significantly inhibited motility and invasiveness of MPNST cells, and these effects were enhanced by the addition of selumetinib. Overall, our results advocate for a combinatorial therapeutic approach for MPNSTs that not only targets the growth and survival via inhibition of MEK1/2, but also its malignant spread by suppressing the activation of BMP2-SMAD1/5/8 pathway. Importantly, these studies were conducted in low-passage patient-derived MPNST cells, allowing for an investigation of the effects of the proposed drug treatments in a biologically-relevant context.

BRAF V600E Mutations Occur in a Subset of Glomus Tumors, and Are Associated With Malignant Histologic Characteristics

Glomus tumors are rare mesenchymal neoplasms with a phenotype akin to the modified smooth muscle cells of the glomus body. Most are benign, but rare examples show malignant histologic characteristics and aggressive behavior. We recently encountered a malignant glomus tumor with BRAF V600E mutation. We sought to study a large cohort for this mutation, with particular attention to associated malignant histologic characteristics. Tumors were classified based on WHO criteria as benign, uncertain malignant potential (glomus tumors of uncertain malignant potential-GT-UMP), or malignant. Tumors were screened for BRAF V600E by immunohistochemistry, and positive staining was evaluated further by Sanger sequencing. A total of 102 glomus tumors were included and classified as benign (57, 56%), GT-UMP (15, 15%) and malignant (30, 29%). Tumors occurred in patients aged 8 to 89.9 years (median: 50.2), without sex predilection (55% men). Most occurred in the superficial soft tissue (84%) and upper extremities (55%). Six of 95 tested cases had BRAF V600E mutation (6%), including 0 of 57 benign tumors, 3 of 14 GT-UMP (21%), and 3 of 24 malignant tumors (12%). Follow-up was obtained for 59 cases (median: 75.7 mo, range: 7.8 to 268.5). Three of 11 malignant tumors (27%) had progressive disease: 1 with metastasis to brain and heart, 1 with enlarging residual disease, and 1 with recurrence. Two of 4 GT-UMP (50%) had progressive disease: 1 with metastasis to lung, and 1 with local recurrence (50%). Three of 44 benign tumors (7%) had local recurrence. Two of 5 patients with BRAF V600E had progression, including 1 GT-UMP with local recurrence and 1 malignant tumor with enlarging residual disease. In summary, BRAF V600E mutation was detected in 6% of glomus tumors, all of which were malignant or GT-UMP. This mutation may be associated with a malignant phenotype, although study of additional cases is needed. In patients with progressive disease, BRAF could be a promising therapeutic target.

Functional Ulnar Nerve Paraganglioma: First Documented Occurrence in the Extremity With Hitherto Undescribed Associated Extensive Glomus Cell Hyperplasia and Tumorlet Formation

Extra-adrenal paraganglioma has never been described in the extremities. A 34-year-old woman complained of an enlarging mass in the right forearm for 18 months. Imaging showed a circumscribed vascular tumor attached to the ulnar nerve; biopsy revealed features of paraganglioma. The resected tumor consisted of zellballen pattern of chief cells staining positively for chromogranin with surrounding S100-positive sustentacular cells. The chief cells contained many neurosecretory granules and mitochondria, whereas the sustentacular cells contained a large amount of rough endoplasmic reticulum and some microfilaments. There was adjacent extensive glomus cell hyperplasia and tumorlet formation. The intraoperative blood pressure dropped abruptly on tumor removal. The serum normetanephrine level decreased from a preoperative level of 1987 pg/mL (normal < 149 pg/mL) to normal after operation. The patient admitted on questioning to a history of paroxysmal attacks of transient palpitation, hand tremors, and sweating; imaging showed no evidence of tumor in other parts of the body, and there was no family history of similar tumor; she remained well 33 months after the operation. This occurrence of functional ulnar nerve paraganglioma with the hitherto undescribed associated glomus cell hyperplasia and tumorlet formation attests to the probable existence of normal sympathetic paraganglia in the extremity and their intimate functional relationship with glomus bodies.

Gastric glomus tumor: clinical conundrums and potential mimic of gastrointestinal stromal tumor (GIST)

Gastric glomus tumor is a rare neoplasm of the gastrointestinal tract that frequently mimics other mesenchymal lesions clinically and radiologically. We present a 70-year-old woman with an incidentally detected submucosal tumor of the antrum that was thought to be a gastrointestinal stromal tumor (GIST). The lesion measured 1.9 cm radiographically and was monitored over a period of 3 years. Multiple biopsies were attempted but did not yield a clear diagnosis. Over time, the lesion increased in size and developed an area of ulceration, prompting a wedge resection. After surgery, a diagnosis of glomus tumor was reached on the basis of histological and immunohistochemical studies. Glomus tumors are neoplasms of perivascular smooth muscle differentiation that can occur nearly anywhere in the body but exhibit a strong predisposition for the skin and subcutaneous tissue. They usually follow an indolent clinical course, although rare cases of metastasis have been reported. Gastrointestinal involvement is uncommon, and when present, the stomach is almost exclusively involved. Preoperative diagnosis may be impossible given the overlapping features with other mesenchymal tumors of the stomach, as illustrated in our case. A literature review of 210 gastric glomus tumors is provided, and important diagnostic pitfalls are highlighted to prevent misdiagnosis. In an era of precision medicine where incidental lesions are increasingly detected by routine endoscopy and imaging, awareness of this rare entity is important, as gastric glomus tumors are generally benign with a favorable prognosis following complete resection.

Genetic Analyses of the NF1 Gene in Turkish Neurofibromatosis Type I Patients and Definition of three Novel Variants

Neurofibromatosis Type I (NF1) is a multi systemic autosomal dominant neurocutaneous disorder predisposing patients to have benign and/or malignant lesions predominantly of the skin, nervous system and bone. Loss of function mutations or deletions of the NF1 gene is responsible for NF1 disease. Involvement of various pathogenic variants, the size of the gene and presence of pseudogenes makes it difficult to analyze. We aimed to report the results of 2 years of multiplex ligation-dependent probe amplification (MLPA) and next generation sequencing (NGS) for genetic diagnosis of NF1 applied at our genetic diagnosis center. The MLPA, semiconductor sequencing and Sanger sequencing were performed in genomic DNA samples from 24 unrelated patients and their affected family members referred to our center suspected of having NF1. In total, three novel and 12 known pathogenic variants and a whole gene deletion were determined. We suggest that next generation sequencing is a practical tool for genetic analysis of NF1. Deletion/duplication analysis with MLPA may also be helpful for patients clinically diagnosed to carry NF1 but do not have a detectable mutation in NGS.

Glomangiomatosis of the sciatic nerve: a case report and review of the literature

Glomus tumors are hamartomas, which tend to occur in sites rich in glomus bodies, such as the subungual regions of digits or the deep dermis of the palm, wrist, forearm, and foot. Very rarely, they may involve peripheral nerves. We describe a patient, who, following surgical resection of a solitary glomus tumor of the left distal sciatic nerve in his teens, had recurrence with development of multiple tumors in the course of the nerve over several years. To our knowledge, this is the only known case of glomangiomatosis involving a major peripheral nerve.

Unusual Glomus Tumor of the Penis

INTRODUCTION

Glomus tumors are benign neoplasms commonly found in subungual regions of the extremities and rarely located in the penis. Misdiagnosis of glomus tumors is common; therefore, symptoms and clinical presentations should be reviewed.

OBJECTIVE

The primary objective of this review article is to emphasize the pathogenesis, pathology, clinical presentation, symptoms, diagnosis, and treatment methods of glomus tumors in order to better identify and manage the condition.

MATERIALS AND METHODS

Research was conducted using PubMed/Medline. The inclusion criteria required glomus tumor to be present on the penis.

RESULTS

Glomus tumors, which appear as symptomatic or asymptomatic lesions, are attributed to dispersion grouping of neoplastic or non-neoplastic lesions in a particular area.

CONCLUSION

Differential diagnosis of glomus tumors includes hemangiomas, neurofibromatosis, epithelial lesions, and spindle-cell lesions. Physical examination and histological findings should be used for diagnosis. Treatment options can be either conservative or invasive, in which the patient undergoes surgical excision.

Refinements in Sarcoma Classification in the Current 2013 World Health Organization Classification of Tumours of Soft Tissue and Bone

The fourth edition of the World Health Organization (WHO) Classification of Tumours of Soft Tissue and Bone was published in February 2013. The 2013 WHO volume provides an updated classification scheme and reproducible diagnostic criteria, which are based on recent clinicopathologic studies and genetic and molecular data that facilitated refined definition of established tumor types, recognition of novel entities, and the development of novel diagnostic markers. This article reviews updates and changes in the classification of bone and soft tissue tumors from the 2002 volume.

Skin glomic tumors referred for local pain and cured by surgical removal

BACKGROUND

Under the definition "glomus tumors" are often erroneously enclosed neoplasms that are absolutely unlike for origin, location, and behavior. Glomus tumors (GTs) are small but extremely painful skin tumors of mesenchymal origin. GTs derive from the neuromyoarterial glomus in adults of middle-age and are generally benign. Due to their small size, diagnosis is often difficult and patients harboring these tumors usually consult many physicians, including sometimes neurosurgeons. More familiar to neurosurgeons are neoplasms as glomus jugular, glomus vagale, and glomus tympanicum that instead all belong to the family of paragangliomas (PGs) and for this reason should not be confused with the aforementioned skin tumors.

METHOD AND RESULTS

Here we present a brief review of these two different classes of tumors and also the clarification of any misunderstanding that may derive from an improper use of the terminology. In order to illustrate why skin tumors may interest neurosurgeons, we have reviewed our institutional series of outpatient surgical procedures. Differential diagnosis with other tumors that appear as cutaneous nodules is also discussed. From January 2012 to May 2015, seven patients harboring a GT (six male and one female) were treated. The age ranged from 34 to 71 years (mean, 54.1). The clinical suspect of GT, was validated by ultrasound (US) and, if necessary, by magnetic resonance imaging (MRI). All patients underwent surgery for total tumor removal. Immediate pain relief was obtained in all the patients, and no recurrences were observed during follow-up. Histology confirmed the diagnosis of GT.

CONCLUSIONS

Subcutaneous painful nodules, originating from the glomus body, are properly called GTs. Unlikely from other tumors, as schwannomas or neurofibromas, GTs are the cause of pain that is disproportionate to their tiny size and that is not associated to neurological disturbances. Surgical treatment allows a complete regression of pain with significant patient satisfaction. Neoplasms originating from neuroepithelial cells, on the contrary, should not be defined as GTs.

Congenital Retroperitoneal Teratoma in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is caused by mutations in the tumor suppressor gene NF1. The increased tumor risk in affected individuals is well established, caused by somatic biallelic inactivation of NF1 due to loss of heterozygosity. Pediatric teratoma has not been reported in individuals with NF1 previously. We report a case of congenital teratoma in an infant with a heterozygous maternally inherited pathogenic NF1 mutation (c.[1756_1759delACTA] and p.[Thr586Valfs*18]). We detected a "second hit" in the form of mosaic whole NF1 deletion in the tumor tissue using multiplex ligation-dependent probe amplification, as a proof to support the hypothesis of NF1 involvement in the pathogenesis of teratoma.

Acceptance and commitment therapy in youth with neurofibromatosis type 1 (NF1) and chronic pain and their parents: A pilot study of feasibility and preliminary efficacy

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder affecting about 1 in 3,500 individuals. Chronic pain is commonly reported among individuals with NF1 and plexiform neurofibroma tumors (PNs). Acceptance and Commitment Therapy (ACT), an empirically supported method for addressing chronic pain, helps individuals re-focus on valued relationships and activities. This pilot study investigated the feasibility and preliminary efficacy of a brief ACT workshop in the NF1 population. Eligible participants included adolescents and young adults (AYA; 12-21 years) with NF1 and chronic pain that interfered with daily functioning and their parents. Patients and parents completed baseline measures of pain interference, pain intensity, functional disability, pain acceptance, depression, and anxiety. Then, AYA and parents participated separately in a 2-day small-group ACT workshop. A telephone booster session occurred 1 month post-intervention. Three-month post-treatment measures were completed by mail. Ten adolescents (4 males; M age = 16.9 years) and seven parents provided baseline and 3-month data. Mean satisfaction with the study was moderate to high (3.9 for patients and 4.6 for parents on a 1-5 scales). Patients and parents reported significant declines in patients' pain interference at 3 months post-treatment. Patient-reported pain intensity significantly declined from baseline to 3 months. Parents reported marginally greater acceptance of their child's pain. No changes emerged in functional ability or mood. Preliminary findings suggest that a brief ACT group intervention is feasible and may help AYA with NF1 and PNs cope with their chronic pain, although larger randomized studies are needed to confirm treatment efficacy. © 2016 Wiley Periodicals, Inc.

An Update on Neurofibromatosis Type 1: Not Just Café-au-Lait Spots and Freckling. Part II. Other Skin Manifestations Characteristic of NF1. NF1 and Cancer

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous syndrome and probably the one best known to dermatologists. Although the genetic locus of NF1 was identified on chromosome 17 in 1987, diagnosis of the disease is still based primarily on clinical observations. The 7 diagnostic criteria of the National Institutes of Health, which were established in 1988, include 3 skin manifestations (café-au-lait spots, freckling on flexural areas, and cutaneous neurofibromas). The age at which these diagnostic lesions appear is variable: onset can be late in some patients while others never develop certain symptoms. Definitive diagnosis may therefore be delayed by years. Although the appearance of the characteristic café-au-lait spots and freckling in the early years of childhood are very suggestive of the disease, these signs are not pathognomonic and, in isolation, do not constitute sufficient evidence to establish a definitive diagnosis. Thus, other diagnoses should be considered in patients whose only symptoms are café-au-lait spots and freckling. By contrast, the presence of multiple cutaneous neurofibromas or at least 1 plexiform neurofibroma is a very specific indication of NF1. Identification of the different types of neurofibroma allows us to confirm the diagnosis and initiate appropriate management.

A Rare Case of Glomus Tumor of the Great Toe: An Analysis of Behavior at This Rare Site

Glomus tumor, originally known as an angioneuromyoma, is a benign neoplasm arising from specialized structures called glomus bodies, involved in thermoregulation. Although it has been reported at a number of sites in the body, this rare tumor is most commonly seen in the subungual areas of the digits of the hand. Only a handful of lesions have been reported in the toes. Because most foot conditions are treated by podiatrists and dermatologists, orthopaedic surgeons are generally unaccustomed to making early diagnoses. The purpose of this case report is to alert the attending surgeon regarding the possibility of glomus tumor as a cause of chronic toe pain. Also it has been observed that the behavior of this tumor varies with the site of occurrence-whether digital or extradigital. So we have extensively reviewed all similar reports in the literature to analyze the behavior of this tumor at this unusual location, apart from comparing it with the more common finger variety, to ensure it possibly is not a misclassification like the chemodectomas that were earlier thought to be glomus tumors.

LEVELS OF EVIDENCE

Therapeutic Level IV: Case Study.

The spectrum of nephrocutaneous diseases and associations: Genetic causes of nephrocutaneous disease

There are a significant number of diseases and treatment considerations of considerable importance relating to the skin and renal systems. This emphasizes the need for dermatologists in practice or in clinical training to be aware of these associations. Part I of this 2-part continuing medical education article reviews the genetic syndromes with both renal and cutaneous involvement that are most important for the dermatologist to be able to identify, manage, and appropriately refer to nephrology colleagues. Part II reviews the inflammatory syndromes with relevant renal manifestations and therapeutic agents commonly used by dermatologists that have drug-induced effects on or require close consideration of renal function. In addition, we will likewise review therapeutic agents commonly used by nephrologists that have drug-induced effects on the skin that dermatologists are likely to encounter in clinical practice. In both parts of this continuing medical education article, we discuss diagnosis, management, and appropriate referral to our nephrology colleagues in the context of each nephrocutaneous association. There are a significant number of dermatoses associated with renal abnormalities and disease, emphasizing the need for dermatologists to be keenly aware of their presence in order to avoid overlooking important skin conditions with potentially devastating renal complications. This review discusses important nephrocutaneous disease associations with recommendations for the appropriate urgency of referral to nephrology colleagues for diagnosis, surveillance, and early management of potential renal sequelae.

Cutaneous and ocular manifestations of neurocutaneous syndromes

Neurocutaneous syndromes are a heterogeneous group of congenital and hereditary disorders with manifestations in the skin and the nervous system, usually together with ocular features that represent diagnostic clues and potential sources of morbidity. Dermatologists and ophthalmologists often need to work together in identifying and managing patients with these conditions; herein, we focus on classic and under-recognized neurocutaneous syndromes. We begin with autosomal dominant genodermatoses characterized by hamartomas and tumors in the skin, eyes, and central nervous system: neurofibromatosis type 1, tuberous sclerosis complex, and PTEN hamartoma-tumor syndrome. This is followed by a discussion of two mosaic disorders, Sturge-Weber syndrome and neurocutaneous melanocytosis. In addition to providing an update on clinical presentations and evaluation of patients with these conditions, we review recent insights into their pathogenesis, drawing attention to relationships among the diseases on a molecular level and implications regarding treatment. We also highlight the major features of other neurocutaneous syndromes that have ocular findings plus pigmentary, vascular, hyperkeratotic, adnexal, connective tissue, photosensitive, and inflammatory manifestations in the skin.

Expression Analyses Revealed Thymic Stromal Co-Transporter/Slc46A2 Is in Stem Cell Populations and Is a Putative Tumor Suppressor

By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the CD31(+) endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-1(+) fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.

A RASopathy gene commonly mutated in cancer: the neurofibromatosis type 1 tumour suppressor

Neurofibromatosis type 1 (NF1) is a common genetic disorder that predisposes affected individuals to tumours. The NF1 gene encodes a RAS GTPase-activating protein called neurofibromin and is one of several genes that (when mutant) affect RAS-MAPK signalling, causing related diseases collectively known as RASopathies. Several RASopathies, beyond NF1, are cancer predisposition syndromes. Somatic NF1 mutations also occur in 5-10% of human sporadic cancers and may contribute to resistance to therapy. To highlight areas for investigation in RASopathies and sporadic tumours with NF1 mutations, we summarize current knowledge of NF1 disease, the NF1 gene and neurofibromin, neurofibromin signalling pathways and recent developments in NF1 therapeutics.