Occult Appendiceal Neoplasms in Acute and Chronic Appendicitis: A Single-Institution Experience of 1793 Appendectomies.

: The incidence of appendiceal neoplasms may have been underreported in the past. Patients undergoing incidental appendectomies or appendectomies for chronic appendicitis may be at higher risk for an incidental appendiceal neoplasm. To determine the incidence of occult appendiceal neoplasms and identify risk factors associated with this pathology, a retrospective review of a pathology specimen database was conducted from November 2007 to December 2011, in a single tertiary care hospital center. All patients with appendectomies were included for analysis (n = 1793). Pathology specimens were grouped based on the indication for appendectomy, and the incidence of appendiceal neoplasms, and patient variables among the groups were compared using χ2 test and Student's t test. A total of 1793 appendectomy specimens met criteria for evaluation. The total number of appendiceal neoplasms was 31 (1.7%). There were 14 neoplasms in 1337 (1.0%) cases of acute appendicitis with 2 in 41 (4.9%) cases of chronic and 15 in 415 (3.6%) cases, where an incidental appendectomy was performed (P < 0.001). Patients with carcinoid tumors were significantly younger than patients with noncarcinoid tumors (P = 0.0001). Indication for operation was the only significant factor for predicting an appendiceal tumor on final pathology. Patients who undergo interval or incidental appendectomies may be at higher risk of appendiceal neoplasm compared with those performed for other indications. Younger patients may be at a higher risk of occult appendiceal carcinoid neoplasms than other age groups. Pathologic diagnosis in specific high-risk patient groups may be the only way to effectively capture these tumors for optimal treatment.