Postirradiation Multiple Minute Digitate Porokeratosis

Abstract

Background: Development of multiple minute digitate hyperkeratoses (MMDH) after irradiation has been reported previously. The keratotic lesions in these cases were confined within the irradiation field, and histopathological examination disclosed a focal column of parakeratosis (cornoid lamella) arising from an epidermis devoid of granular layer. Objective: We describe a 78-year-old woman who developed multiple, discrete, tiny, filiform, keratotic papules on the anterior aspect of the right chest wall, 13 months after postmastectomy cobalt irradiation therapy for mammary infiltrating ductal carcinoma. Conclusion: Postirradiation MMDH represents a peculiar radiation-induced disorder that we believe should be distinguished from other cases of MMDH and included within the spectrum of porokeratosis.