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Objective: The aim of this study is to evaluate neurofibromatosis type 1 (NF1) patients with whole-body MRI (WBMRI) to investigate the frequency of plexiform neurofibromas (pNFs), diffuse neurofibromas (dNFs), and malignant peripheral nerve sheath tumors (MPNSTs)., Materials and Methods: In this retrospective cross-sectional study, between the years 2015 and 2023, 83 consecutive patients with known NF1 underwent a total of 110 WBMRI screenings for MPNST using a standardized institutional protocol. The lesions are categorized as discrete lesions, pNFs, dNFs, and MPNSTs. Histopathology served as the reference standard for all MPNSTs., Results: Among the 83 patients analyzed, 53 (64%) were women and 30 were men (36%) of ages 36.94±14.43 years (range, 15-66 years). Of the 83 patients, 33 have a positive family history of NF1 and positive genetic studies. Seven of 83 (8%) have only dNF, 20/83 (24%) have pNF, 28/83 (34%) have both dNF and pNF, and 28/83 (34%) have neither. Of the 83 patients, eight (9.6%) were diagnosed with nine total MPNSTs. Age range for patients with MPNSTs at time of diagnosis was 22-51, with an average age of 33.4 years. Only one MPNST (11%) developed from underlying pNF 4 years after WBMRI along the right bronchial tree. Three of eight (37.5%) patients with MPNST died within 5 years of pathologic diagnosis., Conclusion: This study suggests the absence of a predisposition for development of MPNST from pNFs and dNFs in the setting of NF1. As such, these lesions may not need special surveillance compared to discrete peripheral nerve sheath tumors., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Background: Neurofibromatosis type 1 is a neurocutaneous genetic disorder caused by mutations in the NF1 gene, resulting in the formation of benign tumors called neurofibromas. The most common type of tumor seen in patients with neurofibromatosis type 1 is the slow-growing and benign neurofibroma, with a subtype called plexiform neurofibroma being particularly common and causing pain, functional impairment, and cosmetic disfigurement., Case Presentation: We report the case of a 20-year-old North African female patient with a history of neurofibromatosis type 1 who presented with a growing mass in her right gluteal region, which was later diagnosed as a giant cutaneous neurofibroma. Imaging studies revealed infiltration in several regions, including the urinary bladder wall, resulting in significant bilateral hydronephrosis. The patient is currently being monitored, and no excisional procedures are planned., Conclusions: Neurofibromatosis type 1 can cause a variety of clinical symptoms, including the development of large plexiform neurofibromas. It is important to closely monitor patients with neurofibromatosis type 1 for the early detection of neurofibromas. Early detection and prompt surgical intervention are essential for preventing complications., (© 2024. The Author(s).)

Neurofibromatosis type 1 (NF1) affects cell growth in neural tissues, resulting in neurofibromas of the internal organs, peripheral nerves and/or autonomic nerves. We describe a highly unusual case of plexiform neurofibroma presenting with lacrimal gland enlargement in an 18 year old male, which led to a diagnosis of NF1.

Purpose:  High-frequency ultrasound allows the accurate identification of neurofibromas in neurofibromatosis type 1 (NF1). This study aimed to analyze the ultrasound features of neurofibromas in children with NF1, to establish a classification based on the clinical and sonographic patterns of the different types of neurofibromas, and to evaluate the interobserver correlation coefficient (κ) of this classification., Materials and Methods:  In this prospective, single referral center observational study, clinical and ultrasound findings of neurofibromas in children diagnosed with NF 1 were analyzed. To identify the ultrasound patterns, a cluster analysis allowing the inclusion of both clinical and ultrasound data was designed. The κ coefficient was calculated using 9 external evaluators., Results:  265 ultrasound scans were performed on a total of 242 neurofibromas from 108 children diagnosed with NF1. Cluster analysis allowed the identification of 9 patterns (Snedecor's F, P < 0.001) classified as "classic" cutaneous neurofibroma, blue-red neurofibroma, pseudoatrophic neurofibroma, nodular subcutaneous neurofibroma, diffuse subcutaneous neurofibroma, congenital cutaneous neurofibroma, congenital plexiform neurofibroma, congenital diffuse and plexiform neurofibroma, and subfascial neurofibroma. The κ coefficient of the interobserver ratings was 0.82., Conclusion:  Patterns identified in the cluster analysis allow neurofibromas to be classified with a very high interobserver correlation., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Background and Objectives: Internal neurofibromas, including plexiform neurofibromas (PNF), can cause significant morbidity in patients with neurofibromatosis type 1 (NF1). PNF growth is most pronounced in children and young adults, with more rapid growth thought to occur in a subset of PNF termed distinct nodular lesions (DNL). Growth behavior of internal neurofibromas and DNL in older adults is not well documented; yet knowledge thereof is important for patient risk stratification and clinical trial design. The primary objective of this study was to evaluate the long-term growth behavior of internal neurofibromas in adults with NF1. Secondary objectives were to correlate tumor growth behavior with patient-specific, tumor-specific, and patient-reported variables., Methods: In this prospective cohort study, internal neurofibromas were identified on coronal short TI inversion recovery sequences on baseline and follow-up whole-body MRIs (WBMRIs). Tumor growth and shrinkage were defined as a volume change ≥20%. The association between tumor growth and patient-specific (baseline age, sex, and genotype), tumor-specific (morphology, location, DNL presence on baseline WBMRI, and maximum standardized uptake value on baseline PET imaging), and patient-reported variables (endogenous and exogenous hormone exposure, pain intensity, and quality of life) was assessed using the Spearman correlation coefficient and Kruskal-Wallis test., Results: Of 106 patients with a baseline WBMRI obtained as part of a previous research study, 44 had a follow-up WBMRI. Three additional patients with WBMRIs acquired for clinical care were included, generating 47 adults for this study. The median age during baseline WBMRI was 42 years (range 18-70). The median time between WBMRIs was 10.4 years. Among 324 internal neurofibromas, 62.8% (56% of PNF and 62.1% of DNL) shrank spontaneously without treatment and 17.1% (17.9% of PNF and 13.8% of DNL) grew. Growth patterns were heterogeneous within participants. Patient-specific, tumor-specific, and patient-reported variables (including endogenous and exogenous hormone exposure) were not strong predictors of tumor growth., Discussion: Internal neurofibroma growth behavior in older adults differs fundamentally from that in children and young adults, with most tumors, including DNL, demonstrating spontaneous shrinkage. Better growth models are needed to understand factors that influence tumor growth. These results will inform clinical trial design for internal neurofibromas., (© 2022 American Academy of Neurology.)

A 16-year-old male presented with solitary occipital plexiform neurofibroma, which had grown slowly over several years to reach giant size, thereby mimicking a "double head." There were no features of neurofibromatosis type 1. Total excision of the neurofibroma was done by infiltrating adrenaline circumferentially around the tumor before scalp incision. The feeding arteries were identified in the dense connective tissue above the aponeurosis and ligated or cauterized. Dissection was then carried out in the loose areolar tissue preserving the periosteal layer. There was no evidence of malignant transformation on histopathology, and 5-year follow-up showed no tumor recurrence., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests: None declared.

Purpose: To report a case of diffuse orbital neurofibroma which displayed an unusual computed tomography (CT) feature., Methods: Results of ocular examination, orbital CT examination and pathological findings in a patient with a space-occupying orbital lesion are presented., Results: Orbital CT evaluation of a male patient, aged one and a half years old, revealed a right orbital lesion with a strongly negative value in Hounsfield units. The preoperative diagnosis was a dermoid cyst. An anterior orbitotomy was performed, and the surgical specimen demonstrated a typical plexiform neurofibroma with routine hematoxylin and eosin staining and immunohistochemical studies., Conclusions: Plexiform orbital neurofibromas may demonstrate a negative Hounsfield value on CT examination.

Unlabelled: Neurofibromatosis type 1 or von Recklinghausen's disease is one of the most common autosomal dominant genetic disorders. Between 29% and 77% of patients may suffer from a wide range of skeletal abnormalities and, thus, patients with neurofibromatosis frequently undergo skeletal scintigraphy, at which time the common peripheral nerve soft-tissue tumors that occur in this syndrome (neurofibromas, plexiform neuromas and neurofibrosarcomas) may be demonstrated., Methods: Single or multiphase 99mTc methylenediphosphonate (MDP) bone scans were performed in five patients with neurofibromatosis as part of their clinical evaluation., Results: We imaged neurofibrosarcomas in three patients, cutaneous neurofibromas in one patient and a plexiform neuroma in one patient., Conclusion: Single- or multiphasic bone scans may localize common soft-tissue tumors in neurofibromatosis.