Squamous cell carcinoma arising in an oral lichenoid lesion.

BACKGROUND: Oral lichen planus, or OLP, is a chronic inflammatory mucocutaneous disease that frequently involves the oral mucosa. Lichenoid dysplasia, or LD, refers to lesions that could be mistaken clinically for OLP but have histologic features of dysplasia and a true malignant predisposition. Published case reports of OLP conversion to squamous cell carcinoma, or SCC, have created a great deal of controversy about the true nature of OLP, highlighting the need to verify its clinical diagnosis histologically.

CASE DESCRIPTION: The authors document the development of SCC in a 58-year-old woman with an oral lesion diagnosed clinically as OLP and described histologically as having lichenoid features with dysplastic changes. The time from the initial diagnosis of oral lichenoid lesions to the patient's return visit to the medical center with clinically evident cancer was three years and eight months. The SCC developed in the labial mucobuccal fold and left mandibular edentulous ridge, which had undergone multiple biopsy procedures.

CLINICAL IMPLICATIONS: This case does not provide answers to the ongoing controversy about the innate propensity of OLP to become malignant. However, in view of both the common occurrence of OLP and unresolved issues regarding its premalignant potential, this case report illustrates the need for histologic confirmation and close follow-up of patients with clinical lesions that have lichenoid features.