Clinical and Sonographic Classification of Neurofibromas in Children with Neurofibromatosis Type 1 – A Cluster Analysis

Abstract

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 (Snedecorʼs 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.

Zusammenfassung

Ziel Hochfrequenz-Ultraschall ermöglicht die genaue Identifizierung von Neurofibromen bei Neurofibromatose Typ 1 (NF1). Ziel dieser Studie war es, die Ultraschallmerkmale von Neurofibromen bei Kindern mit NF1 zu analysieren, eine Klassifikation basierend auf den klinischen und sonografischen Mustern der verschiedenen Neurofibromtypen zu erstellen und den Interobserver-Korrelationskoeffizienten (κ) dieser Klassifikation zu bewerten.

Material und Methoden In dieser prospektiven Beobachtungsstudie an einem einzigen Referenzzentrum wurden die klinischen und sonografischen Befunde von Neurofibromen bei Kindern mit der NF1-Diagnose analysiert. Zur Identifizierung der Ultraschallmuster wurde eine Clusteranalyse durchgeführt, die sowohl klinische als auch Ultraschalldaten berücksichtigte. Der κ-Koeffizient wurde mithilfe von 9 externen Bewertern berechnet.

Ergebnisse 265 Ultraschalluntersuchungen wurden an insgesamt 242 Neurofibromen von 108 Kindern mit NF1-Diagnose durchgeführt. Die Clusteranalyse ermöglichte die Identifizierung von 9 Mustern (Fisher-Snedecor-Verteilung, p < 0,001), die als „klassisches“ kutanes Neurofibrom, blau-rotes Neurofibrom, pseudoatrophes Neurofibrom, noduläres subkutanes Neurofibrom, diffuses subkutanes Neurofibrom, kongenitales kutanes Neurofibrom, kongenitales plexiformes Neurofibrom, kongenitales diffuses und plexiformes Neurofibrom und subfasziales Neurofibrom klassifiziert wurden. Der κ-Koeffizient der Interobserver-Bewertungen betrug 0,82.

Schlussfolgerung Die in der Clusteranalyse identifizierten Muster ermöglichen die Klassifizierung von Neurofibromen mit einer sehr hohen Interobserver-Korrelation.

Key words

pediatrics - neurology - point of care - musculoskeletal system - ultrasound - neurofibromatosis 1

Publication History

Received: 18 December 2020

Accepted: 06 August 2021

Article published online:
24 November 2021

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