S4C8P2-1: The patterns are lichenoid and cell-rich. Green arrows point to plasma cells. At the dermal-epidermal interface and in the basal unit of the epidermis, there is a high component of migratory histiocytes (red arrows). The superficial unit of the epidermis is thin but well-defined; the infiltrates of lymphoid cells do not extend into it ( a lipid rich membrane has obliterated the inter-cellular space). Small vessels have swollen endothelium. The process is erosive at the dermal-epidermal interface; the rete ridges are effaced (secondary lues).

S4C8P2-3: As in many lichenoid reactions, the band-like infiltrates fill not only the papillary dermis, but also the perifollicular connective sheath. The papillary dermis and the perifollicular dermis are components of the adventitial dermis; they commonly are similarly affected by inflammatory processes. The infiltrates erode the basal layer of the follicular epithelium. The patterns are lichenoid in the classic sense. The infiltrates in their interactions with epithelium produce lytic defects in the epithelial domain. These defects are the basic feature of a lichenoid reaction. A lichenoid reaction is a lytic process; it is cell-mediated immunity in a lytic phase. Recognition, that  lichenoid reactions have an extremely variable life-history, brings the wide range of histologic patterns of lesions in this category into perspective.

S4C8P2-4: In this area in the lower portion of the dermis, a small vein is associated with prominent infiltrates of lymphocytes, histiocytes, and plasma cells. The inflammatory cells involve the wall of the vessel and the vascular adventitia. Plasma cells are often more numerous in perivascular infiltrates in the deeper portions of the reticular dermis than in the infiltrates of the papillary dermis (2nd lues).