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PEMPHIGUS (TIER 2)
(CONTINUED)
Pemphigus foliaceus is a disease affecting the cells of the superficial unit of the epidermis. Some examples show prominent psoriasiform patterns (S6C14P8-5). In some examples, epidermal changes are subtle; clefts in, or above, the granular layer may be small and poorly developed.
Individual keratinocytes of the granular layer become angulated; they are defined by an increased prominence of the spaces among cells. Some of the clefts may be outlined by necrotic (dyskeratotic), granular cells
(ghost cells) (S6C13P7-1).
Hailey-Hailey disease
(familial [pemphigus-like] basal unit acantholytic disease) usually shows a defect at the intermediate zone (the zone between the basal unit, and the superficial unit).It is also characterized by acantholysis and dyskeratosis affecting the adjacent basal unit (S6C13P7-2 & 3, & S6C14P8-1). The patterns
in some examples of pemphigus vulgaris could be confused with a lesion of Hailey-Hailey disease, if a prominence of acantholytic cells in the defect is the sole criterion (S6C14P8-6).
Although pemphigus foliaceus
commonly is free of inflammatory cells in the epidermis, there are examples with focal collections of lymphocytes and histiocytes; such patterns in the epidermis might be confused with those of a spongiotic dermatitis (S6C14P8-2). In addition, some examples are associated with infiltrates of neutrophils in the defect in, or near, the granular layer (S6C14P8-3 & 4).
Iwatsuki K, et al: Can pemphigus vulgaris become pemphigus foliaceus? J Am Acad Dermatol 1991;25:797-800.
DARIER DISEASE
Darier disease, an acantholytic disorder; can be accommodated in the category of the epithelial nevi. The histologic features include intraepidermal clefts
and suprabasilar acantholysis, and dyskeratosis.
In lesions of Darier disease, both the superficial and basal units of the epidermis usually are hyperplastic (S6C15P9-1-4). Focally, they tend to be intact; in the intact areas, the epidermis shows hyperkeratosis, a prominent granular layer, and elongated rete
ridges.
Focally, within the lesions of Hailey-Hailey disease, the basal unit of the epidermis shows supra-basilar acantholysis. In contrast to the tendency for the
superficial unit of the epidermis to remain intact as they do in lesions of Hailey-Hailey disease (S6C15P9-5), in lesions of
Darier’s disease, an acantholytic (and cytolytic) defect may extend through the superficial unit of the epidermis to the level of the keratin layer; the keratin layer generally shows parakeratosis (a variation
in which parakeratotic debris is spoken of as “corps grains”). The defect, involving both the basal and superficial units of the epidermis, contains acantholytic cells. Bordering the intra-epidermal defects, the
epidermis is hyperplastic and shows hypergranulosis. Some of the cells in the neighboring superficial unit are individually hypertrophied. They have a large, round nucleus and show clearing of the cytoplasm.
Centrally, about the nucleus, these plump, enlarged cells show prominent keratohyaline granules.
In some examples of Hailey-Hailey disease, the patterns focally overlap with those of Darier disease (S6C15aP9a-1-3): acantholysis results in disruption of inter-cellular bonds; the disruption affects both the
superficial and the basal units; a defect, sometimes flask-shaped, forms in the area of acantholysis; it contains rounded, acantholytic (dyskeratotic) cells.
In lesions of Darier’s disease, rounded, dyskeratotic keratinocytes of the granular layer are corps ronds (S6C15P9-4). Flattened parakeratotic cells along the surface of the lesion are corps grains. Dermal papillae along the floor project into the
defect in villous-like patterns (S6C15P9-1-4). Inflammation in the dermis is variable; in hypertrophic forms, it usually is a prominent feature.
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