Inflammatory appendix mass in patients with acute appendicitis: CT diagnosis and clinical relevance.

The purpose of our study was to analyze the clinical relevance of computerized tomography (CT) in providing the diagnosis of inflammatory appendix mass (IAM) in patients with acute appendicitis. The CT images of 134 patients were reviewed. Two groups of patients were made according to the presence (group 1; n = 21) or the absence (group 2; n = 113) of IAM. Clinical signs of patients, CT features, complications at surgery, and histological examinations were noted. Inter-observer agreement was assessed by using kappa statistics. Twenty-one patients presenting with CT features of IAM were diagnosed. An excellent inter-observer agreement (κ = 0.94) was assessed for the diagnosis of IAM. No significant statistical difference in the age distribution was observed between patients with IAM (mean age 55) and patients without (mean age 45) (p = 0.2232). No clinical sign showed a statistically significant association with the presence of IAM (p = 0.707) or with complication encountered at surgery (p = 0.180). Delay to CT examination was 5.4 days in patients presenting with CT features of IAM and of 1.7 days for patients presenting without (p = 0.0001). Conversely to acute appendicitis complicated by simple perforation (p = 0.153) or peri-appendicular abscess (p = 0.501), acute appendicitis presenting with IAM showed a statistically significant association with complications encountered at surgery (p = 0.0003) and the need for conversion to open surgery (p = 0.001). Performing CT in complicated acute appendicitis provides the diagnosis of IAM. Distinction of IAM appeared to be of clinical relevance, since immediate surgery in IAM was statistically associated with surgical complications and conversion to open surgery in our study.