S5C21P14EDPerstans

S5C21P14-2: In this example of EDP, a lichen-planus-like pattern is represented. There is a lytic defect at the extremities of two neighboring rete ridges. Along the periphery of the defect, there is no basal layer; the defect extends into the basal unit (lichen planus-like qualities). The defect contains necrotic keratinocytes that are closely associated with histiocytes and lymphocytes. Some of the associations might be characterized as “satellite cell necrosis.” At the extremity of the defect, colloid bodies are clustered. The papillary dermis shows lamellar fibrosis. In other areas, the pattern of the papillary dermis is less defined. There are spotty perivascular infiltrates of lymphoid cells.

S5C21P14-3 (EDP): The basal unit of the epidermis is hyperplastic; the basal layer shows vacuolar changes. Lymphocytes and histiocytes intermingle mostly among cells of the altered basal layer. There is irregular pigmentation of the basal layer in the area of the lichenoid reaction. The focal character of the lesion complicates the interpretation. For this pattern, a sharp distinction between spongiosis and a lichenoid reaction is difficult to define; the two reactions share certain features.


S5C21P14-1: Erythema dyschromicum perstans (EDP) is another variant of cell-poor lichenoid dermatitis. In this example, there are mild liquefactive changes at the dermal-epidermal interface. Lymphoid cells, and histiocytes are sprinkled among basal keratinocytes. Migratory histiocytes are loosely spaced in the slightly widened, fibrotic papillary dermis. There are mild perivascular infiltrates of lymphoid cells with scattered melanophages. The basal layer is damaged; the basal unit is thin, but represented. The eosinophilic deposit near the lower, right corner is a deposit of colloid (colloid degeneration).

S5C21P14-4: Focal lichenoid patterns, some of which are associated with lytic defects at the tips of rete ridges, are a feature of this lesion of EDP. To the right, melanophages are prominent in the widened papillary dermis. There is mild hyperkeratosis.

S5C21P14-5: The scattered lytic defects at the dermal-epidermal interface of this lesion of EDP define the patterns as a lichen planus-like reaction. The defects seem to localize at the tips of rete ridges.

S5C21P14-6: In this field, the rete patterns are partially effaced. There is irregular pigmentation of the basal layer of the epidermis. Melanophages in the dermis identify the pattern as a melanoderma. In turn, the epidermal patterns take on significance; they qualify as a senescent lichenoid reaction (EDP).

S5C21P14-7: In this senescent lichenoid reaction, there are spotty areas of liquefaction degeneration at the dermal-epidermal interface. Melanophages are present in the dermis. The lesion has qualities which might be characterized as a pigmented, senescent lichenoid reation (pigmented poikiloderma in clinical setting of EDP). In an appropriate clinical setting, this pattern also could be in keeping with changes seen in “pigmented pruritic patches” of the back (Waisman). The latter disorder shares features with those of macular amyloidosis; it may represent a variation of macular amyloidosis in which amyloid deposits are not a histologic feature.

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