POMC and neoplasm: In the group UT, the largest tumor diameter was negatively correlated with baseline ACTH (r = −0.391; p < 0.001) and positively correlated with second-day plasma cortisol after 1 mg DST (r = 0.306; p < 0.001), while in the BT group, the largest diameter of the two tumors showed a positive correlation with the second-day plasma cortisol after 1 mg DST (r = 0.309; p = 0.012) (Figure 5).