Atypical perioral pigmentation leading to the diagnosis of neurofibromatosis type 1 and a low-grade central nervous system lesion in a pediatric patient: Unmasking the silent threat

Neurofibromatosis type 1 (NF1) is a common neurocutaneous disorder typically presenting with café-au-lait macules (CALMs) and neurofibromas, with a known predisposition to central nervous system (CNS) neoplasms. We report an unusual presentation of a 9-year-old male whose chief complaint was perioral pigmentation persisting for four years. Although lacking cutaneous neurofibromas, the presence of multiple CALMs prompted ophthalmologic evaluation, which revealed Lisch nodules, thereby satisfying the diagnostic criteria for NF1. Subsequent neuroimaging to screen for optic pathway gliomas uncovered a significant intracranial mass lesion suggestive of a pilocytic astrocytoma, necessitating surgical intervention. This case highlights perioral pigmentation as a potential atypical marker for phakomatoses and underscores the critical importance of a low threshold for neuroimaging in pediatric NF1 patients to detect silent CNS tumors.