A retrospective study of oral lichen planus patients with concurrent or subsequent development of malignancy

Oral lichen planus (OLP) carries a very small probability of becoming malig nant. Our Finnish series comprised eight patients suffering from OLP and co ncurrent or subsequent oral squamous cell carcinoma over a 10-year period. The mean-interval between the histologically suggested initial diagnosis of OLP and carcinoma was 3.4 years. An oral ulcer asa clinical manifestation of malignant change appeared in seven of these eight patients; five of the eight died of carcinoma on average 13 months (range 7-20) after the final s quamous cell carcinoma diagnosis. These eight patients were compared to eig ht control OLP patients without malignant transformation matched as to foll ow-up time, age, gender, sites of the lesions, etc. We could discover no hi stological features leading to malignant development. However, the clinical ly unilateral atrophic/erosive type of OLP more often preceded the malignan t change, compared to the situation for control patients, in whom the most prevalent type was the bilateral reticular OLP. However, the probability se ems to be very small. (C) 1999 Elsevier Science Ltd. All rights reserved.