Oral atrophic lichen planus and oral lichenoid lesion malignant transformation: report and management of two cases

BACKGROUND: There is an ongoing debate in the literature whether patients with oral lichen planus (OLP) carry an increased risk of developing a squamous cell carcinomas. Nevertheless, there is a tendency to accept that there is. The annual malignant transformation rate amounting less than 0.5%. This chronic disorder mainly affects middle-aged people. The etiopathogenesis is still poorly understood. There is no effective treatment and there are no preventive measures either. An important obstacle in the discussion on the possible potentially malignant character of oral lichen planus is caused by the lack of clear clinical and histopathologic diag- nostic criteria of oral lichen planus, resulting in a poor clin- icopathologic correlation in the diagnosis. One of the major problems of interpretation of malignant potential studies of OLP is the inexistence of strict diagnostic criteria to differentiate lichenoid processes. Some studies have included cases of OLP with OLL and vice versa. The differentiation between OLP and OLL has become important, since the latter might have a greater malignant potential. For this reason, it is important to establish precise clinical and histopathological criteria of differentiation of the lesions. CASE REPORT: 1st) A 73 years old woman with a 12 months histological diagnosis of oral lichen planus localized on tongue dorsum, previously biopsied and studied in a differ- ent structure, came to our attention to investigate an ulcerative lesion on tongue midline. No smoking habit, alcohol abuse, anemia or previous malignancies diagnosis were referred; topical corticosteroid therapy was referred. An incisional biopsy was performed showing lichenoid lesion, atypia and high grade of dysplasia at histological examination. Subsequently, lesion was radically removed with wide excision margins. Microscopic examination returned diagnosis of mild differentiated squamous cell carcinoma arose on lichenoid lesion. Resection margins were clean without perineural or vascular invasion. After 18 months follow-up, symptoms of dull pain and burn sensation were referred. Tongue dorsum was macroscopically altered, with an ulcer-like lesion surrounded by edematous mucosa. Consequently, an incisional biopsy was performed showing the presence of a low differentiated squamous cell carcinoma. Lesion was radically excised, margins were widened and examined with frozen sections. Patient underwent to bilateral SND (level I-III) and RTP. Histological examination returns a diagnosis of recurrent pT1 pN1 micro-invasive squamous cell carcinoma. Microscopic signs of lichenoid lesion were still evident. 2nd) A 74 years old woman, with a 20 months history of