Dilemma of mucosal appendicitis: a clinico-pathological entity? A retrospective cohort study

The presence of mucosal inflammation within appendicectomy specimens is poorly described in the literature, and there is debate regarding the clinical significance of this histological finding. The aim of this study is to correlate clinical and radiological data with histologically confirmed acute mucosal appendicitis (MA).

A retrospective cohort study was performed to identify all patients who underwent appendicectomy over 5 years at Caboolture Hospital. Data were collected in regards to clinical Alvarado score, pathological specimen findings, radiological findings and coincidental conditions, and comparison made between MA and negative appendicectomy groups.

A total of 1347 appendicectomy specimens and data were reviewed. Of these, 219 (16%) specimens were microscopically confirmed to have acute mucosal inflammation, 150 (68%) were females. Median age was 19 ± 14 years. A total of 243 (18%) were histologically negative. There was a statistically significant difference in mean Alvarado score in the MA group (5.0 ± 1.9 versus 4.3 ± 1.8, P = 0.0002). Patients with MA are more likely to report migratory pain (48.4 versus 31.4%, P = 0.0001) and rebound tenderness (24.9 versus 14.6%, P = 0.002). Computed tomography and ultrasound scans were negative in 74.1 and 72.6%, respectively, in patients with MA. More MA patients benefited from appendicectomy compared with the negative appendicectomy group (82 versus 63%, P = <0.0001).

There is a subgroup of patients with MA who are young females with have low Alvarado scores, have non-diagnostic imaging, and may represent almost one-fifth of appendicectomy specimens. This study supports the probability that MA is a pathological entity.