S5C23P16-Lichens-misc



S5C23P16-1: Lichenoid patterns are encountered in a variety of clinical settings; in some examples, the patterns are subtle. Erythema dyschromicum perstans is an example. At this magnification, one clue, that this may be a cell-poor lichenoid reaction, is the focal loss of rete patterns. In addition, there are spotty areas of liquefaction degeneration at the dermal-epidermal interface. Inflammatory infiltrates are mild and perivascular. There are focal infiltrates at the dermal-epidermal interface in association with the liquefactive changes.


S5C23P16-2 (EDP): At higher magnification, the areas of liquefaction degeneration at the dermal-epidermal interface are spotty and mild. The pattern is that of a cell-poor lichenoid process . Melanophages are present in the papillary dermis.

S5C23P16-3: Lichen sclerosis et atrophicus (LS&A) of the genitalia is more variable in pattern than is the case with LS&A in other sites. In this field, the epidermis is hyperplastic in psoriasiform patterns. Loose infiltrates of lymphoid cells fill at least two neighboring dermal papillae; they hug the epidermis. The infiltrates also involve the basal unit of the overlying epidermis ( lichenoid patterns of primary type).

S5C23P16-4 (LS&A): In this field, the patterns are clearly lichenoid; they have lichen planus-like qualities. The superficial unit of the epidermis is hyperplastic; individual keratinocytes of this unit are hypertrophied in a characteristic manner. The lichenoid process has resulted in lysis of the basal layer (with loss of a defined basal unit). Just to the right of the center of the field, there is a lytic defect that is outlined by reduplicated basement membrane. Green arrows identify migratory histiocytes with at least one dendritic histiocyte in the defect (green arrowhead). Red arrows identify colloid bodies ( apoptotic cells).

S5C23P16-5: At the dermal-epidermal interface, hyalinization of the papillary dermis is just beginning. In this example of LS&A, the process is rather limited at the dermal-epidermal interface; the hyalin is deposited in basement membrane-like patterns. As the material forms, the lymphoid cells are pushed away from the epithelial interface. The hyalin functions as an “immunologic barrier.” In other fields, the patterns of hyalinization were fully developed; they were less membranous. They more uniformly involved the papillary dermis. The patterns at the dermal-epidermal interface suggest that basement membrane materials may have a role in the sclerosing process.

S5C23P16-6: The pattern in this field resembles LS&A, but is too densely fibrotic. It could also be compared to patterns in superficial morphea. The basement membrane is thickened and hyalinized. Hyperelastosis focally is a feature. Vessels are rather sparse, in distribution, and ectatic (radiodermatitis).

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