Clinical significance of variable histomorphologic findings related to mucosal inflammation in negative appendectomy

The aim of the study was to investigate the clinical significance of various histomorphologic findings related to mucosal inflammation in negative appendectomy. We reviewed histopathologic findings of 118 negative appendectomies and correlated them with the appendicitis inflammatory response (AIR) score and appendiceal diameter. Among 118 patients with negative appendectomy, 94 (80%), 73 (78%) and 89 (75%) patients displayed mucosal inflammation, high neutrophil score (neutrophil count ≥10/5 high power field and surface epithelial flattening, respectively. Out of 118 patients with negative appendectomy, mucosal inflammation, high neutrophil score and surface epithelial flattening were associated with higher risk group according to the appendicitis inflammatory response (AIR) score (p < 0.05, respectively). In addition, mucosal inflammation, high neutrophil score and surface epithelial flattening were frequently detected in 118 negative appendectomies, compared with 24 incidental appendectomies (p < 0.05, respectively). In an analysis of 77 negative appendectomy patients with appendiceal diameter data available, increased appendiceal diameter was positively correlated with luminal inflammation, high neutrophil score and surface epithelial flattening (p < 0.05, respectively). In conclusion, mucosal inflammation, high neutrophil score and surface epithelial flattening in negative appendectomy may be relevant to patients’ signs and symptoms, especially in cases with no other cause of the abdominal pain.