Dyskeratotic degeneration of epidermal cells in pityriasis rosea: light and electron microscopic studies.

We studied biopsies from twenty-nine patients with pityriasis rosea. All specimens showed features of subacute or chronic dermatitis as previously reported, but sixteen cases (55%) had dyskeratotic cells within the epidermis. Ultrastructurally, these cells contained an aggregation of tonofilaments, many vacuoles and intracytoplasmic desmosomes. Previously, only non-specific histological changes had been described in pityriasis rosea, but the presence of dyskeratotic cells seems to be a significant feature.