Disseminated spiked hyperkeratosis. An unusual discrete nonfollicular keratinization disorder

An unusual nonfollicular keratinization disorder was observed in a father and his son, and in an unrelated woman. The disorder began during the second decade of life and gradually became more widespread and more pronounced thereafter. The dermatosis is characterized by tiny, rough, keratotic spikes giving the skin a raspy fell on palpation. Microscopically, the lesions showed a thick compact corneum without structural changes in the underlying epidermis except for moderate epidermal cell hyperplasia and some reduction in keratohyalin content.