Abstract
A 77-year-old Japanese male was referred to our department for an often-blistering skin lesion on his left wrist, which had developed about 3 years ago. At the initial visit to our department, a clinical examination revealed a 16x18-mm erythematous nodule with a blistered surface on the left wrist. A histological examination showed mild acanthosis with acantholysis and dyskeratotic keratinocytes, especially in the lower layers of the epidermis. The upper dermis showed a moderately dense cell infiltrate containing numerous eosinophils. Based on these clinical and histological findings, we made a diagnosis of acantholytic dyskeratotic acanthoma (ADA). The topical application of difluprednate ointment reduced the erythematous areas, and blisters no longer formed. ADA is a rare form of acanthoma, which histologically presents with acantholysis and dyskeratosis. ADA usually presents as a solitary nodule on the trunk. There have been no reports of ADA with blister formation to date. In our case, since the acantholysis was mainly localized to the lower layers of the epidermis and the lesion was located in the wrist area, we hypothesized that the blistering may have been caused by external forces, such as rubbing in daily life.
