Multiple minute digitate hyperkeratoses.

A familial case of multiple minute digitate hyperkeratoses is reported. Hundreds of tiny, spiked, keratotic papules were scattered on the trunk and limbs. Microscopically, the lesions showed digitiform orthohyperkeratosis with tenting of the epidermis. Neither atypical epidermal cells nor a dermal infiltrate were observed. This disease has three types: familial, sporadic and postinflammatory. We have analysed the histopathological features of all the cases reported to date. While the familial and sporadic types are similar, the lesions in the postinflammatory type are composed of parakeratotic columns with an invaginated epidermis. Although morphological analysis may not provide any clues to pathogenetic differences, it seems reasonable to assume that the postinflammatory type is an entity different from the other two forms.