Figure 3: Differential diagnoses of labial LP. a: Lichen simplex chronicus (persistent rubbing): the patient persistently rubbed his upper teeth against the lower lip. Lesion is intensely keratotic. b: Actinic cheilitis: diffuse blurring of the vermilion border and keratosis. Biopsy revealed a very superficial squamous cell carcinoma. c: Erythema multiforme: more marked edema, congestion, haemorragic crusts, and necrosis than would be expected in LP. d: Lupus erythematosus: a well-demarcated erythemato keratotic plaque that, contrarily from LP, typically spreads from the vermilion to the adjacent skin [19].