Granular cells in oral lichen planus

OBJECTIVE AND DESIGN: Three cases of granular cells associated with oral li chen planus (OLP) have been reported to date, which prompted us to look for the presence of granular cells in a consecutive series of 250 cases of OLP in the period 1996-1998. RESULTS: Only one case with granular cell changes was encountered in that s eries, H&E stained slides as well as direct immunofluorescence examination showed characteristics compatible with OLP. Part of the subepithelial conne ctive tissue was replaced by a granular cell proliferation; S-100 protein w as diffusely expressed in all granular cells, whereas no expression of smoo th muscle actin was observed. CONCLUSION: Based on these findings it seems unlikely that the granular cel ls in the present case represent a so-called 'oral ceroid granuloma', The p resence of granular cells might rather have been a reactive phenomenon trig gered by the inflammatory infiltrate or a granular cell tumour (GCT). Wheth er the simultaneous presence of a GCT and OLP in this particular case was b ased on a causal relationship or on coincidence still remains unknown.