Hypergranulotic dyscornification: a distinctive histologic pattern of maturation of epidermal epithelium present in solitary keratoses.

Hypergranulotic dyscornification is an appellation proposed to designate a newly recognized distinctive pattern of epidermal maturation that is analogous to other epithelial reaction patterns such as epidermolytic hyperkeratosis, focal acantholytic dyskeratosis, cornoid lamellation, pale-cell acanthosis, and follicular mucinosis. The name "benign hypergranulotic keratosis with dyscornification" is proposed to specify solitary keratoses with digitated epidermal hyperplasia that exhibit this exceptional pattern of cornification. This abnormal type of cornification is characterized by hypergranulosis. A pale-staining basophilic substance is present intercellularly within the upper spinous layer and the hyperplastic granular layer. Overlying the thickened granular layer in foci at tips of epidermal papillations are orthokeratotic mounds of large, dull, eosinophilic staining corneocytes that are sharply demarcated from the thickened granular layer. Basophilic keratohyalin granules are focally retained within these corneocytes. There is overlying compact orthokeratosis that extends across the entire lesion. The compact orthokeratosis is slightly basophilic, and lies below a laminated and basket-weave orthokeratotic stratum corneum. There is a predominantly lymphocytic infiltrate at the base of these neoplasms with some spongiosis. There is parakeratosis focally present in the stratum corneum overlying these individual areas of abnormal cornification. The histopathologic and clinical findings in eight lesions that exhibit hypergranulotic dyscornification, a heretofore undescribed unique pattern of epidermal cornification, are presented.