SATB2 Expression in Rectal and Appendiceal Neuroendocrine Tumors (NETs). The vast majority of rectal NETs (A) demonstrated diffuse, strong SATB2 expression (B). While most appendiceal NETs were also SATB2-positive, they showed a greater range of expression. This tubular carcinoid (C) displays diffuse, strong staining (D), this EC-cell tumor (E) shows only slightly weaker staining (F), while this second EC-cell tumor (G) demonstrates more modest staining (H) (original magnification of each image 200x).