A Rare Presentation of Congenital Melanocytic Nevus on the Tongue and Lower Lip Mucosa

Congenital melanocytic nevi (CMN) are rare lesions with significant diagnostic challenges, particularly when they occur in atypical locations such as oral mucosa. This study is the first in India to document a case of CMN involving both the tongue and lower lip mucosa, highlighting the need to understand these uncommon manifestations for accurate diagnosis and effective management, given their potential risk of malignant transformation. A 36-year-old male with asymptomatic pigmented lesions on the dorsal tongue and lower lip mucosa underwent detailed clinical and dermoscopic evaluation using a Fotofinder Medicam 1000 under polarized light. Clinical examination revealed hyperpigmented patches on the dorsal tongue and discrete macules on the lower lip mucosa. Dermoscopy demonstrated circumscribed dark brown to black pigment globules on the tongue and a unique “fish scale” pattern on the lower lip. A diagnosis of oral CMN was made, and regular follow-up was recommended. To the best of our knowledge, this case represents the first reported instance in India of CMN involving the tongue and lower lip mucosa simultaneously, with distinctive dermoscopic findings. It underscores the diagnostic value of dermoscopy and the importance of vigilant monitoring for these rare presentations to mitigate malignant risks.