Grading pancreatic neuroendocrine neoplasms by Ki-67 staining on cytology cell blocks: manual count and digital image analysis of 58 cases

Although Ki-67 labeling on CB can be used to grade PanNENs, limitation exists, particularly for grade 2 tumors. The method of counting makes a difference: MC is more accurate than DIA. The major reasons of discordance include non-tumor cell contamination and insufficient sampling.