Fig. 2

Malignant transformation in Case 4 showing clinical pictures and correlating histopathologic features in biopsy (haematoxylin–eosin staining) at initial presentation (a, b) and malignant transformation (c, d). a She had symmetric reticular and atrophic lesions on the bilateral buccal mucosa and tongue and showed no positive to metal patch test. The lesions did not improve with removal of the metal prosthesis close to the tongue and was clinically and histopathologically diagnosed with OLP. b Biopsy revealed histopathologic features of OLP, including parakeratosis with basal cell liquefactive degeneration, a band-like predominantly lymphocytic infiltrate adjacent to basal cells. c Two years and 5 months later, the lesion had transformed into SCC. d Biopsy revealed SCC