Neutrophil count in the normal appendix and early appendicitis: diagnostic index of real acute inflammation

It is generally accepted that the uninflammed appendix does not contain neutrophils. In view of that, we searched for the presence of neutrophils in 60 uninflammed appendectomies and compared the findings with the neutrophil count in 20 cases of early appendicitis. In the uninflammed appendix, the upper third of the mucosa showed a mean of 0.75 neutrophils (N) per 5 high power fields (HPF), 4.71 N/5 HPF in the middle third, and 2.70 N/5 HPF in the deep third. At the suberosa, a mean of 3.41 and 3.32 N per 10 post-capillary venules in respectively longitudinal and transverse sections of the organ were present. The number of neutrophils in the mucosa showed a positive correlation with the number in the subserosa. In the early appendicitis we observed a mean of 12.53 N/5 HPF in the upper third, 11.33 N/5 HPF in the middle third, and 13.0 N/5 HPF in the deep third; at the subserosa, a mean of 4.95 N/10 post-capillary venules in transverse sections and 4.45 N/10 post-capillary venules in longitudinal sections was observed. No positive correlation between N in the mucosa and subserosa was observed. The count of N in the mucosa of normal appendix and early appendicitis showed a significant difference (P <.005). We conclude that, although present, not more than 10 neutrophils/5 HPF are found in the mucosa of uninflammed appendixes. Neutrophil count in the lamina propria should support the diagnosis of "normal" appendix and could be an indicator for suspecting early appendicitis, preventing underdiagnosis.