S1C21P11-EM&LE


S1C21P11-1: The infiltrates are composed of lymphocytes and histiocytes; the dermal-epidermal interface is straight. Lymphocytes and histiocytes have migrated through the basement membrane. They collected among basal keratinoctyes. There are vacuolar changes in the basal layer (small, rounded defects); a basal unit of the epidermis is not well defined (blue arrows identify a poorly defined interface between the basal unit and the superficial unit). Degenerating, acidophilic, basal keratinocytes are present near the basement membrane zone. In the basal unit, there is focal, cellular disarray. The epidermis is rich in migratory histiocytes (yellow arrows). Individual, necrotic keratinocytes have migrated (been carried) upward. Above the center of the field, necrotic cells are clustered and viable keratinocytes have formed a whorl about the cluster (whorled transepidermal elimination). The keratin layer is little altered. The dermal infiltrates are lymphoid and rich in migratory histiocytes. In this restricted field, the patterns define a basic reaction pattern of lichenoid type ; the reaction pattern is erythema multiforme-like (this is a lesion of erythema multiforme). To the left, there is a collection of extravasated red blood cells at the dermal-epidermal interface.


S1C21P11-2:The changes of an erythema multiforme-like reaction are well-developed. There is necrosis of the basal layer with upward migration of necrotic keratinocytes. Lymphocytes and histiocytes have collected at the D-E interface. The necrosis of individual basal cells has progressed on the left to the formation of a sub-epidermal cleft. On the right, the patterns are those of an intra-epidermal vesicular disorder. In some areas, the vesicular patterns have a reticulated quality. There is papillary dermal edema. Dermal infiltrates are perivascular.

S1C21P11-3: This is clearly a cell-poor process at the dermal-epidermal interface. The basement membrane is focally coarsened and has fibrinoid qualities; it is reduplicated and there are vacuolar changes on both sides of the basement membrane. Migratory histiocytes are represented on both sides of the altered basement membrane. There are few lymphocytes. The papillary dermis is edematous. Cells of the basal layer are thin; focally, there are defects in the basal layer. Cells with features of a hyperplastic superficial unit extend to the basal layer; there is no evidence of a defined basal unit. Cells of the superficial unit are individually hypertrophied (enlarged and polygonal). They show prominent tonofibrils and intercellular bridges. The long axis of each keratinocyte above the basal layer is parallel to the skin surface. This pattern serves as a model for the definition of a basic reaction pattern, the lupus erythematosus-like pattern (lupus erythematosus). The patterns in the epidermis above the basal layer are in keeping with terminal differentiation; there is atrophy of the basal unit.

S1C21P11-4: To the left, the basal layer shows degenerative changes; there is a small lytic defect at the dermal-epidermal interface. The reaction at the dermal-epidermal interface is cell-poor. At the tip of the papilla near the blue arrows, the basement membrane is thickened and hyalinized; there are vacuolar changes in the basal layer of the epidermis. To the right, in areas, the basal layer is preserved and hyperpigmented. A basal unit is not well defined. A vessel in the dermis shows mural deposits of hyalin (blue arrows in dermis). The papillary dermis contains melanophages (pigment lost to the dermis as a consequence of damage to basal keratinocytes) ( lupus erythematosus).

S1C21P11-5: In this field from a lesion of lupus erythematosus, the characteristic, cell-poor lichenoid pattern is represented; lymphoid cells form infiltrates on both sides of a thickened basement membrane. This homogeneous, acidophilic deposit (in linear patterns) in the basement membrane zone is a distinctive feature of a lesion of lupus erythematosus.

S1C21P11-6: Follicles are usually involved in lesions of lupus erythematosus. In discoid lupus erythematosus, perifollicular lymphoid infiltrates often are cell rich with band-like components in a widened perifollicular sheath. In this example, the infiltrates are cell-poor. Blue arrows identify migratory histiocytes. Green arrows identify a “lichen planus-like” lytic defect in the epithelial domain.

S1C21P11-7: The definition of a lupus erythematosus-like reaction pattern has application for the characterization of many cutaneous lesions of dermatomyositis. Usually, the basement membrane changes are less conspicuous in lesions of dermatomyositis. Blue arrows identify some thickening and hyalinization of the basement membrane; focally, it is reduplicated. The combined patterns in the regions at the tips of the green arrows have apoptotic qualities. The interface changes have a lichenoid quality; they are cell-poor. The epidermal superficial unit is hyperplastic in patterns of terminal differentiation. A basal unit, as such, is poorly defined. The granular layer is hyperplastic.

up one page; if at tier 3 then up to respective “parent” chapter

next page, same tier

back one page, same tier, spatial sequence

Two navigation buttons to the left (green) provide access to web sites. All the beige buttons to the right provide access to photomicrographs and parent CHAPTERS (-x) of this SECTION. The mauve buttons provide access to other SECTIONS of this site.