Iris Dermoscopy: A Clinical Tool for Early Detection and Monitoring of Lisch Nodules in “Neurofibromatosis Type-1”

Abstract Background: Lisch nodules (LNs) are melanocytic iris hamartomas and among the most specific diagnostic markers for neurofibromatosis type 1 (NF-1). Their detection, particularly in dark irides, can be challenging without slit-lamp examination. Dermoscopy may offer a simple, non-invasive alternative. Aims: To describe the dermoscopic characteristics of LNs in NF-1 and assess the role of dermoscopy in diagnosis and monitoring. Patients and methods: A cross-sectional observational study was conducted over six months at a tertiary-care Genodermatoses Clinic. Twelve patients with confirmed or suspected NF-1 underwent detailed clinical evaluation. Polarized iris dermoscopy was performed using DermLite DL4 (10×), attached to a Samsung S21 FE. LNs were assessed for morphology, number, color, and vascular pattern. Associations with clinical variables and other NF1 diagnostic criteria were analyzed statistically. Results: The mean age was 28.3 ± 14.2 years, with a female predominance (58.3%), and 75% had dark irides. Dermoscopy detected LNs in 91.6% patients, with a mean of 4.8 ± 3.9 nodules per patient. LNs were identified in 3/12 paediatric patients (25%) in whom café-au-lait macules (CALMs) were the sole sign, enabling fulfilment of National Institutes of Health (NIH) diagnostic criteria. Nodule count correlated significantly with age ( r = 0.67, P = 0.04), disease duration ( r = 0.71, P = 0.03), and CALMs burden of >6 (6.8 vs. 3.1, P = 0.04). Smartphone imaging detected nodules in only 41.7% of cases. Interobserver agreement was 91.6%, with examinations being rapid, non-contact, and well-tolerated. Conclusion: Dermoscopy is a valuable adjunct for detecting LNs and enhances diagnostic accuracy in NF-1. Its portability, user-friendly and non-invasive nature make it suitable for routine screening and longitudinal monitoring, particularly in paediatric populations and resource-limited settings. Limitations: Small sample size; no direct comparison with slit-lamp examination.