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Increased risk of mucinous neoplasm of the appendix in adults undergoing interval appendectomy.

IMPORTANCE
The role of interval appendectomy after conservative management of perforated appendicitis remains controversial. Determining the etiology of perforated appendicitis is one reason to perform interval appendectomies.


OBJECTIVE
To determine whether adult patients undergoing interval appendectomy experience an increased rate of neoplasms.


DESIGN
Retrospective study.


SETTING
A single tertiary care institution.


PARTICIPANTS
All patients 18 years or older who underwent appendectomy for presumed appendicitis from January 1, 2006, through December 31, 2010. EXPOSURES Appendectomy for presumed appendicitis.


MAIN OUTCOMES AND MEASURES
Underlying neoplasm as the cause of presentation for presumed appendicitis. Demographic data, clinicopathologic characteristics, interval resection rate, and complication data were collected and analyzed.


RESULTS
During the study period, 376 patients underwent appendectomies. Interval appendectomy was performed in 17 patients (4.5%). Neoplasms were identified in 14 patients (3.7%); 5 of those tumors occurred in patients who had undergone interval appendectomy (29.4%). Nine neoplasms were mucinous tumors (64.3%), including all neoplasms associated with interval appendectomies. The mean age of all patients with appendiceal tumors was 49 years (range, 35-74 years).


CONCLUSIONS AND RELEVANCE
Mucinous neoplasms of the appendix were found in 5 of 17 patients (29.4%) undergoing interval appendectomy. Interval appendectomies should be considered in all adult patients, especially those 40 years or older, to determine the underlying cause of appendicitis. A multi-institutional study to determine the generalizability of these findings is warranted.