Immunohistochemical expression of estrogen receptor (ER, Panel B), progesterone receptor (PR, Panel C), and mitotic activity (Ki-67, Panel D) in EIN with squamous morules (Case 8) shows squamous morules (asterisk) are essentially negative for ER, PR, and Ki-67, in contrast with glandular (arrow) components. Panel A, hematoxylin and eosin stain.