Hypergranulotic Dyskeratotic Acanthoma: Another Histologically Distinctive Acanthoma.

Various acanthomas have been named based on their distinctive histopathologic patterns. Hypergranulotic dyskeratotic acanthoma represents another acanthoma with a distinctive histopathologic pattern that has been rarely reported. In this article, clinical and histological features of hypergranulotic dyskeratotic acanthoma are delineated. A retrospective analysis was performed of cases with diagnosis or suggested diagnosis of hypergranulotic dyskeratotic acanthoma between 2012 and 2017 from 2 dermatopathology laboratories. Forty-eight potentials were identified, of which 18 cases met the inclusion histologic criteria. Most cases came from women (78%) with a mean age of 53 years, and the thigh was the most common site involved. All cases had the following histopathological findings: (1) verrucous or digitated epidermal hyperplasia, (2) hyperkeratosis dominated by basketweave or compact orthokeratosis, (3) hypergranulosis involving the breadth of the lesion, and (4) presence of enlarged, often indistinctly bordered, keratinocytes with cytoplasm characterized by a blue-gray granular peripheral zone sometimes showing outstretched desmosomes and central perinuclear eosinophilic zones, a combination of findings representing slowly evolving dyskeratosis. Retrospective nature and a small sample size are the major limitations of the study. In sum, hypergranulotic dyskeratotic acanthoma can be easily distinguished from other acanthomas based on their repeatable histopathological findings.