LAUSR

Of note, there can be clinical and histological overlap between hypertrophic lichen planus and welldifferentiated squamous cell carcinoma due to the florid epithelial hyperplasia present in both conditions. Although proliferation indices may be similar, elevated p53 expression and the presence of perforating elastic fibers are more suggestive of keratoacanthoma than hypertrophic lichen planus. In our patient, because of the absence of hypertrophic lichen planus clinically, and the distinct and rapidly evolving papulonodular appearance of the lesions, we did not feel that histopathologic diagnostic confusion was likely.