S8C22P9-1: For review, the basic patterns of a leukocytoclastic angiitis are represented. The epidermis is relatively uninvolved. The papillary dermis and the upper portion of the reticular dermis are edematous. Lymphatic vessels are ectatic. There are perivenular infiltrates of inflammatory cells (preponderantly neutrophils); the infiltrates extend into the interstitium of the reticular dermis among the vessels.

S8C22P9-3: The pattern is that of a lymphocytic vasculitis with extravasation of red blood cells. The epidermis shows hyperplasia of the superficial unit and compact hyperkeratosis.

S8C22P9-4: The epidermal patterns contribute a “lichen planus-like” quality. The rete ridges are shortened and thin; they have pointed extremities. There are perivascular infiltrates in the upper portion of the reticular dermis. Focally, the infiltrates extend into the neighboring interstitium to produce band-like patterns; the infiltrates do not hug the epidermis. The papillary dermis is edematous. There are collections of extravasated red blood cells to the right of the two follicles. The pattern qualifies as a lichenoid lymphocytic vasculitis. A lesion in the category of the pigmented purpuras should be considered in the differential diagnosis.

S8C22P9-5: In this lesion, the pattern of a lymphocytic vasculitis with papillary dermal edema is represented. The papillary dermal edema is marked; the changes are sufficient to qualify as impending sub-epidermal vesiculation. The epidermis shows hyperplasia of the superficial unit and intra-cellular edema (peri-nuclear vacuoles). The keratin layer is not significantly altered. Somewhat similar patterns may be seen in the setting of the dermal variant of erythema multiforme. Drug eruption should be considered in the differential diagnosis; eosinophils are present in the inflammatory infiltrates.