While there is consensus on how to treat acute appendicitis, the most suitable treatment for an appendiceal inflammatory mass is still debated. This study compares the outcomes of operative and nonoperative management. We retrospectively evaluated 119 patients (2007-2011) with an appendiceal inflammatory mass, 85 of whom were treated nonoperatively and 34 operatively. Of the nonoperative patients, 69 did not receive interventional treatment and 16 underwent percutaneous drainage of an accompanying abscess; the data for these patients were analyzed separately. Of the noninterventional managed patients, 49 (71.0%) experienced at least one recurrence and 37 (53.6%) ultimately needed an acute surgical or radiological intervention. Of the 16 patients who underwent percutaneous drainage, 7 (43.8%) experienced at least one recurrence and 6 (37.5%) underwent an acute surgical or (second) percutaneous intervention. None of the operated patients had a recurrence and the incidence of complications was 17.6%. The incidence of underlying malignant tumor in our study population was 5.9%. In 35 patients, the definitive diagnosis remained unclear because the patients did not undergo surgery or follow-up colonoscopy after nonoperative treatment. The rate of extensive (ileocecal + hemicolonic) resection in all operated patients was 30.8%. We conclude that the high rate of recurrence and intervention in the nonoperative group and the high proportion of these patients who did not receive adequate follow-up despite the relatively high rate (5.9%) of bowel malignancy support the operative management of an appendiceal inflammatory mass. Noninterventional management or a percutaneous intervention should be reserved as a bridge to surgery for patients with a large accompanying abscess or as treatment for patients with significant comorbidity. If nonoperative treatment is chosen, follow-up colonoscopy is mandatory to exclude malignancy.