Hyperkeratotic variant of porokeratosis Mibelli with dermal amyloid deposits.

We report a case of hyperkeratotic variant of porokeratosis Mibelli with dermal amyloid deposits. A 66-year-old man presented with multiple brownish keratotic lesions on the lower extremities, a verrucous nodule on the third toe of the left foot and brownish verrucous plaques on the buttocks for several years. Histopathological examination of the hyperkeratotic plaque in the right gluteal region revealed extreme hyperkeratosis and cornoid lamella. In the papillary dermis, there were prominent eosinophilic amorphous materials which were positive to Dylon staining. Treatment with oral etretinate resulted in a remission of the skin lesions in this case.