title: Histological analysis of appendices removed during interval appendectomy after conservative management of pediatric patients with acute appendicitis with an inflammatory mass or abscess.
abstract: OBJECTIVE
  To clarify the role of interval appendectomy (IA) in pediatric patients with acute appendicitis with an appendiceal inflammatory mass or abscess, we histologically analyzed the appendices removed during IA.
  
  
  METHODS
  We treated 355 consecutive pediatric patients with acute appendicitis and reviewed the admission charts of patients who started conservative management (CM). The histology of the appendix removed during IA was also examined. The relationships among the clinical features, appendicolith formation at the time of IA and histological findings were analyzed by stepwise regression analyses.
  
  
  RESULTS
  (1) CM was started in 48 patients (13.5 %). Recurrence or a remaining abscess was observed in nine patients (18.8 %). (2) Histopathological changes, particularly foreign body reaction with fibrosis and infiltration of inflammatory cells, were observed in about half of the specimens. (3) In a stepwise regression analysis, the presence of an appendicolith at IA was correlated with an appendicolith at diagnosis, foreign body reaction in the appendix and a decrease in the inflammatory reaction at diagnosis.
  
  
  CONCLUSIONS
  More than half the patients had strong histopathological changes in the appendix, suggesting a high possibility of recurrence. The presence of appendicolith formation at IA, which is a risk factor for recurrence, was influenced by the presence of an appendicolith at diagnosis, foreign body reaction in the appendix and the inflammatory status of patients at diagnosis. These clinical findings are indications for IA.
authors.affiliation: Division of Pediatric Surgery, Department of General Surgical Science, Gunma University Hospital, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan, sayasaya@gcmc.pref.gunma.jp.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Otake
authors.forename: Norio
authors.initials: N
authors.lastname: Suzuki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Toki
authors.forename: Akira
authors.initials: A
authors.lastname: Nishi
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Kuroiwa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
mesh_terms: D000038:Abscess / Q000473:pathology* / Q000601:surgery*; D000208:Acute Disease; D001062:Appendectomy / Q000379:methods*; D001064:Appendicitis / Q000473:pathology* / Q000601:surgery*; D001065:Appendix / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005355:Fibrosis; D005549:Foreign-Body Reaction / Q000473:pathology; D006801:Humans; D008297:Male; D012008:Recurrence; D012307:Risk Factors