Figure 1: Cutaneous papillomas of the skin. (a) Neck, cow. Multiple exophytic, irregular verrucous papilloma masses arising in the skin. (b) Histopathological section showing papillary projections composed of a hyperkeratotic epidermis with a central collagenous core (10x). (c) Interdigitated epidermal and dermal papillary projections (shown by arrows, 10x). (d) Fibroblast proliferation, collagen deposition, and lymphocyte infiltration (shown by arrows, 10x). (e) Koilocytes (arrows) and keratinocytes with swollen perinuclear halos (40x). (f) Koilocytes with clear cytoplasm and pyknotic nuclei (shown by arrows, 40x, stained with H&E).