Microscopic examination of a hematoxylin-eosin–stained biopsy specimen from the right arm showed a dense, wedge-shaped, upper dermal inflammatory infiltrate, with the apex extending into the dermis and the base abutting the epidermis. The inflammatory infiltrate was composed of lymphocytes, large atypical lymphoid cells (Figure 4, arrow), and a few neutrophils. The large atypical lymphocytes had large vesicular nuclei with prominent nucleoli, which stained positive with CD30 immunostain. Focal spongiosis and mild lymphocytic exocytosis that focally obscured the dermoepidermal junction were noted in the overlying epidermis. The blood vessels had thick walls with plump endothelial cells and contained intraluminal neutrophils. These features were consistent with type A LyP.
Recurrent Pruritic Papules in a 74-Year-Old Man. Arch Dermatol. 2001;137(10):1367-1372. doi: