MKI67 and neuroendocrine neoplasm: Two patients died due to their pituitary adenomas: one died from metastasized neuroendocrine tumor (NET) originating from an atypical ACTH-producing adenoma, with the Ki-67 index increasing from 2% to over 30%; the other died from tumor burden associated with a lactotrophic pituitary NET, which had a Ki-67 index of 4%.