Clinical behaviour of malignant transforming oral lichen planus.

AIMS At present oral lichen planus (OLP) is classified among precancerous conditions but very few data are available in literature regarding prognosis of OLP-related cancers. The aim of this paper is to evaluate clinical long-term behaviour of OLP-related oral squamous cell carcinomas (OSCCs). METHODS Clinical history and data from follow-up regarding 21 patients undergoing malignant transformation of OLP have been critically revised. RESULTS In a mean time of 2.6 years from diagnosis of OLP, patients developed OSCCs. Histopathologically, two carinomas showed a moderate degree of differentiation, while the others were well differentiated. Six (28.5%) were in situ OSCC, in eight (30%) was found a microinvasive pattern of infiltration, one was a stage II tumour and the remaining (6 cases) were stage I tumours. During follow up, four patients (19%) have developed another OSCC in a mean time of 11 months from the first occurrence. In two men (10% of cases), multiple OSCCs occurred and in five cases (24%) lymph nodal metastases were detected. CONCLUSIONS Our study points out an alarming tendency in developing second primary metachronous tumours (33.3%) of the oral cavity and nodal metastases (23.8%), especially if we consider their early stages. Thus we always recommend a strict follow-up of OLP patients with clinical oral and neck examination every 2 months for 6-9 months since OSCC diagnosis is made and, after, three times a year.