Sézary syndrome. Patient presenting with (A) erythroderma. (B) Band-like infiltrate of atypical lymphoid cells in superficial dermis with formation of intraepidermal (Pautrier) microabscesses. (C) Strong expression of CD279 (PD-1) by neoplastic T cells is a useful marker to differentiate Sézary syndrome from erythrodermic inflammatory dermatoses. Original magnification ×40 (B-C); hematoxylin and eosin (B) and immunoperoxidase (C) stain.