Disseminated cicatricial pemphigoid in a child and in an adult. Ultrastructural diagnostic criteria and differential diagnosis with special reference to acquired epidermolysis bullosa.

The first case of an infant affected with a rare, disseminated variant of benign cicatricial pemphigoid is described, showing the same ultrastructural features of initial blister formation as an adult patient. These consist in edematous changes within the superficial dermis caused by vesiculation or dissolution of cellular and noncellular connective tissue elements, coalescing into subepidermal blisters. Differential diagnosis excludes other nonhereditary bullous disorders because of the ultrastructure of the dermo-epidermal junction in nascent blisters and in perilesional skin. In spite of evident clinical, histological, and immunohistological similarities as well as controversial and confusing immunological studies, acquired epidermolysis bullosa can be clearly separated from our case by a diagnostic hallmark on the electron-microscopical level, i.e., band-like IgG depositions beneath the basal lamina. This is demonstrated in comparing the two cases of disseminated cicatricial pemphigoid with three patients suffering from acquired epidermolysis bullosa, thus providing evidence that disseminated cicatricial pemphigoid and acquired epidermolysis bullosa are two distinct nosologic entities.