Fig. 4.

The biopsy shows a psoriasiform epidermal hyperplasia (case 20). Intercellular edema is observable within the epidermis. The suprapapillary plates are thickened. There is focal exocytosis of lymphocytes into the epidermis. (A) A perivascular and intersitital lymphohistiocytic and eosinophilic infiltrate is noted in the dermis (hematoxylin and eosin [H and E], 100 ×). Higher power magnification shows the composition and architectural disposition of the dermal inflammatory cell infiltrate whereby it is both interstitial and perivascular. The degree of interstitial histiocytic infiltration imparts a subtle interstitial granulomatous quality to the infiltrate. (B) Note the significant tissue eosinophilia (H and E, 200 ×)