S13C24P22-3: At this margin of the bulla, the basal layer of the epidermis shows degenerative changes; there is disappearance of a defined basal layer (cytolysis). The defect contains condensed fibrin. The vessel, to the extreme right of the field, has a slightly thickened wall that is somewhat hyalinized.

S13C24P22-4: Some examples of pityriasis lichenoides have prominent psoriasic qualities, as in this example. The epidermis shows acanthosis and elongated rete ridges. Green arrows point to a collection of extrasavated red blood cells.

S13C24P22-5: The patterns are psoriasiform. Focally, hyperplasia of the basal unit is a prominent feature. The rete patterns are not as regular as those usually seen in classic examples of psoriasis. The perivenular infiltrates of lymphoid cells are more prominent than usually seen in an uncomplicated lesion of psoriasis.

S13C24P22-6: Focally, in the basal unit of the epidermis, the rich infiltrates of lymphoid cells contribute a pityriasic quality to the patterns. The nuclei of the lymphoid cells in the epidermis seem to be larger than those of cells in the perivascular infiltrates (see next page in sequence).