Nevus Sebaceus With Novel HRAS Sequence Variant Mutation Misdiagnosed As Alopecia Areata

A 12-year-old girl initially misdiagnosed with alopecia areata was later found to have a nevus sebaceus (NS) with a novel HRAS sequence variant mutation. Despite treatment with topical corticosteroids and minoxidil, her condition did not improve. Physical examination revealed a well-demarcated, yellowish-pink plaque on her scalp, which was bald but contained fine vellus hairs. A biopsy confirmed the presence of NS with incidental compound nevus, and genetic testing identified a missense HRAS p.G12V variant. The case highlights the importance of accurate diagnosis in congenital scalp lesions.