An interesting case of subungueal squamous cell carcinoma in a 13-year-old girl is presented. The tumor presented as a pseudo-fibrokeratoma with melanonychia on the index finger. Biopsy was diagnostic and treatment consisted of Mohs micrographic surgery and secondary intention wound healing. This is one of the youngest patients ever reported with subungueal squamous cell carcinoma, and there is only one more case of pseudo-fibrokeratoma and melanonychia reported as initial skin lesions.