RESUMO
BACKGROUND: Oral squamous cell carcinoma (OSCC) of the gingiva represents less than 6% of intraoral carcinomas. CASE REPORT: A 51-year-old male patient presented with a history of a symptomatic red spot with periods of remission and recurrence in the mandibular gingiva. On clinical examination red and white areas were observed in the gingiva, particularly around the left lower molars. Diagnosis of gingival lichen planus was suspected and topical corticosteroids was prescribed. A good clinical response was observed with reduction of symptom. The patient remained in regular follow-up and after 9 months, the lesion suddenly changed, became ulcerated and diagnosis of OSCC was established. CONCLUSION: The clinical manifestation of OSCC can eventually mimic other even more common lesions of the oral mucosa, highlighting the importance of considering OSCC as differential diagnosis of any unexplained and persistent lesion in the oral cavity.