S5C28P21-Lichens, misc



S5C28P21-1 (lymphocytic infiltrate of the dermis): The infiltrates are perivenular; they spare the papillary dermis and the epidermis.

S5C28P21-2 (lymphocytic infiltrate of the dermis [polymorphic light eruption]): Collagen bundles of the reticular dermis are thin and widely spaced.



S5C28P21-3: This area of a lesion shows liquefaction degeneration of the basal layer of the epidermis (green arrows). To the left of the central dermal papilla a defect contains globular, pale pink deposits . The basal layer of the epidermis is interrupted by the globular deposits; the process has qualities of a cell-poor lichenoid reaction. The deposits have the tinctorial qualities and the histochemical characteristics of amyloid (lichen amyloidosis).

S5C28P21-4: Amyloid deposits clearly involve the basal unit of the epidermis; they have interrupted the basal layer of the epidermis (lichen amyloidosis).

S5C28P21-5: With a congo red stain, the amyloid of both lichen amyloidosis and macular amyloidosis is metachromatic. Some of the deposits are present in the cytoplasm of keratinocytes in the epidermis at the tip of the involved dermal papilla (green arrows).

S5C28P21-6: In this example of macular amyloidosis, amyloid deposits are prominent in the dermis. Red arrows point to deposits in keratinocytes in the epidermis; some of the cytoplasmic deposits in the epidermis are dot-like, near the nucleus (Sirrus red?).

S5C28P21-7: Perhaps, it is far-fetched to include rosacea in the category of lichenoid-lymphocytic vasculitides but, in some lesions, the epidermis often shows both effacement of rete ridges, as well as spotty areas of liquefaction degeneration at the dermal-epidermal interface. Inflammatory infiltrates generally are perivascular and perifollicular in the mid and upper portions of the reticular dermis. In these same areas, the connective tissue tends to be pale (mid-dermal atrophy). Ectasia of vessels is most prominent in the dermis at about the level of the sebaceous glands.

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