title: CT diagnosis of mesenteric adenitis.
abstract: OBJECTIVE
  To quantify how frequently mesenteric adenitis clinically mimics appendicitis and to determine its appearance at computed tomography (CT).
  
  
  METHODS
  The medical records of 651 consecutive patients with an admission diagnosis of appendicitis were reviewed to determine how often mesenteric adenitis was the discharge diagnosis. The CT scans of a separate group of 18 patients with a discharge diagnosis of mesenteric adenitis were reviewed. These patients were part of a group of 100 consecutive patients prospectively evaluated with CT of the appendix for clinically suspected appendicitis.
  
  
  RESULTS
  Fifty of 651 patients (7.7%) with an admission diagnosis of appendicitis had a discharge diagnosis of mesenteric adenitis. Mesenteric adenitis constituted 50 of the 252 (19.8%) discharge diagnoses other than appendicitis. All 18 CT scans of mesenteric adenitis showed three or more nodes that measured at least 5 mm in shortest axis clustered in the right lower quadrant, with a normal appendix identified. Eight patients had associated ileal or ileocecal wall thickening.
  
  
  CONCLUSIONS
  Mesenteric adenitis is an important clinical mimic of appendicitis. It appears at CT as clustered, enlarged mesenteric lymph nodes with a normal appendix, and there may be associated ileitis or ileocolitis noted.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Rao
authors.forename: J T
authors.initials: JT
authors.lastname: Rhea
authors.forename: R A
authors.initials: RA
authors.lastname: Novelline
mesh_terms: D001064:Appendicitis / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008640:Mesenteric Lymphadenitis / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed