Epidermolytic hyperkeratosis in nevi. A possible marker for atypia.

Epidermolytic hyperkeratosis (EH) has been described as a reaction pattern in a variety of solitary skin lesions. We have noted that EH seems to occur more frequently in association with atypical than with typical acquired nevi. To support or refute this observation, the prevalence of EH in 250 cases of atypical compound nevi and in 250 cases of typical compound nevi was determined. EH was identified in 10 cases of atypical compound nevi and in two cases of typical compound nevi, which is a statistically significant difference with p value < 0.02. Since EH occurred in only 4% of atypical nevi examined, it should not be considered a diagnostic criterion. However, the identification of EH in otherwise histologically typical nevi should prompt the pathologist to make sure the lesion has been adequately sampled.