Figure 1.

Analysis of classical histological atypical features for invasive non-functional pituitary neuroendocrine tumors (NF-PitNETs). The existence of CS invasion was evaluated by gadolinium (Gd)-enhanced T1-weighted images. There were no significant differences in Ki-67 and p53 expression or mitotic count between NF-PitNETs with CS invasion and NF-PitNETs without CS invasion (Ki-67 and mitotic count, student’s t-test; p53, chi-squared test). Black arrow: tumor cell showing positive Ki-67 expression (Original magnification, ×20).