S7C4P1-3: At higher magnification, the process again has features of a peculiar, cell-poor lichenoid reaction with a focal, lytic defect at the dermal-epidermal interface on the right. The basal unit is hyperplastic; it shows intra- and inter-cellular edema.

S7C4P1-4: The basement membrane (blue arrows) is preserved. Vacuoles are present on both sides of the membrane. The basal unit is hyperplastic, it shows intra- and inter-cellular edema. Centrally, a small lytic defect in the basal unit at the basement membrane level contains eosinophils (green arrows). Cytopathic changes are not a prominent feature. The edematous papillary dermis contains extravasated red blood cells (herpes gestationis).

S7C4P1-5: The pattern in this example of herpes gestationis might be compared to those of the preceeding case. Defects at the dermal-epidermal interface have an undulating quality; the rete ridges seem to remain partially attached. Over the defects, a well-defined basal unit is not a prominent feature.

S7C4P1-6: The defects at the dermal-epidermal interface are multifocal. Those rete ridges, which remain attached to the dermis, define the lateral walls of the defects. In the areas of attachment, the basal unit is preserved and edematous. The defects contain fibrin  and a sprinkling of inflammatory cells, including eosinophils. Eosinophils are also prominent in the edematous basal unit of the neighboring epidermis. The papillary dermis is edematous and compressed along the floor of the defect.

S7C4P1-7: In this area (blue arrows), there is an edematous disruption of the basal unit of an hyperplastic epidermis. The arrows point to the basement membrane zone. Clearly, the pattern is different from that of  common spongiotic dermatitis. The reaction is an edematous disruption of the basal unit in reticulated patterns. Evidence that the reaction might be mediated at the level of the dendritic histiocyte and lymphocytes is not obvious at the morphologic level (herpes gestationis).

S7C4P1-8:  In this field from this example of herpes gestationis, edema of the basal unit of the epidermis and of the papillary dermis is demonstrated. Dendritic histiocytes and lymphocytes are not a prominent feature. There is a sprinkling of migratory histiocytes near the dermal-epidermal interface.

S7C4P1-9: The edematous qualities of a lesion of herpes gestationis are represented in this field. The basal unit of the epidermis and the papillary dermis are edematous. Migratory histiocytes are represented at both the basement membrane level and among neighboring keratinocytes. Eosinophils (red arrows) are present in the infiltrates.