A 53-year-old man presented to the urologic department with a small tumor on the glans penis. He had been receiving dermatologic treatment of lichen planus on the glans penis for 10 years. On physical examination, the tumor displayed an irregular surface. Because of a suspicion for malignancy, a biopsy was performed. The pathologic diagnosis was squamous cell carcinoma; therefore, partial penectomy was performed. The detailed pathologic findings revealed that the white raised areas adjacent to the tumor consisted of lichen planus with mild cytologic atypia. The final pathologic diagnosis was squamous cell carcinoma (pT1N0M0) originating from lichen planus. No recurrence had been seen as of 4 years postoperatively.