Hailey-Hailey Disease—An Electron Microscopic Study

Eighteen lesions from four adult patients with Hailey-Hailey disease were biopsied and studied by electron microscopy. Both acantholysis and abnormal keratinization were seen occurring together or independently in basal, prickle, and granular cells, while only abnormal keratinization was seen in corneum cells. Acantholysis was manifested by bizarre microvillar changes (elongation, thinning, branching, clubbing, “quill-pen” constriction, and detachment) which seemed to precede widening of intercellular spaces and tonofilament-desmosome changes. Abnormal keratinization was represented by electron dense abnormally thickened bundles of tonofilaments; in basal cells these were straight or wavy; in prickle and granular cells they often appeared whorled. In corneum cells the persistance of tonofilaments and other cytoplasmic organelles signified abnormal keratinization. Neither acantholysis nor abnormal keratinization is a necessary prerequisite for the other, yet both events are probably explainable by a single gene defect. Thus far, the combination of bizarre microvillar changes and abnormal tonofilament configurations occurring in the same lesion is pathognomonic of Hailey-Hailey disease.