Twice malignant transformation of hypertrophic lichen planus.

Lichen planus is a chronic mucocutaneous T-cell-mediated disease, the cause of which remains unknown. The first case of lichen planus that transformed into squamous cell carcinoma was reported in 1903. The presented study concerns the case of a 62-year-old woman in whom twice malignant transformation of hypertrophic lichen planus in the dorsal part of the left foot developed. Several studies have pointed out the malignant transformation potential of lichen planus. Epidemiological studies from the last 20 years have revealed a malignant transformation rate of 0.27% per year, emphasizing the importance of the clinical follow-up of lichen planus patients.