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.