Malignant transformation of oral lichen planus after 6 years: a case report.

Lichen planus (LP) is a chronic or recurrent autoimmune mucocutaneous inflammatory disease. The etiology is uncertain, and it is considered to originate from a multifactorial process. A diagnosis can be made clinically if the disease presents with classic patterns of oral or skin lesions; if these patterns are absent, a biopsy is necessary to establish a diagnosis. Although the World Health Organization has classified oral LP (OLP) as an oral potentially malignant disorder, there is controversy in the literature. Malignancy usually occurs around 60 years of age, with a slight predilection for women. The objective of this case report is to describe a possible occurrence of this process. A 53-year-old woman who sought treatment for oral lesions in 2018 was diagnosed with OLP with epithelial dysplasia and underwent standard treatment with a topical corticosteroid. After ceasing to attend follow-up examinations, the patient continued periodontal treatment with different providers. In 2024, she developed a lesion on the maxillary right alveolar ridge that led to tooth loss in the region. A biopsy was performed, and histopathologic evaluation of the specimen led to a diagnosis of squamous cell carcinoma. There are several differential diagnoses for the clinical forms of OLP, in addition to the possibility of manifestation of concomitant pathoses, and the final diagnosis must reflect a combination of clinical and histopathologic examinations. Patients should be advised about the importance of returning for follow-up appointments, as malignant transformation of OLP may occur.