title: Significance of proximal margin involvement in low-grade appendiceal mucinous neoplasms.
abstract: BACKGROUND
  Appendiceal adenomas and low-grade appendiceal mucinous neoplasms (LAMNs) confined to the appendix are cured by appendectomy. However, involvement of the proximal margin raises concern for residual disease. Some patients with a positive margin at appendectomy undergo cecal resection to eliminate a perceived risk for tumor recurrence or dissemination, although that likelihood is assumed rather than demonstrated.
  
  
  OBJECTIVE
  To determine whether involvement of the proximal appendiceal resection margin by adenoma or LAMN is a risk factor for local development of recurrence or pseudomyxoma peritonei.
  
  
  METHODS
  Appendiceal adenomas and LAMNs confined to the appendix were considered for the study if they showed neoplasia or dissecting mucin at the proximal margin. The presence or absence of residual tumor in cecal resections was determined. Follow-up data were obtained from clinical records.
  
  
  RESULTS
  Sixteen patients (14 female, 2 male) with LAMN (n = 15) or adenoma (n = 1) and an involved proximal resection margin were identified, including 9 with neoplastic epithelium within the lumen and 7 with acellular mucin in the appendiceal wall at the margin. Six patients underwent cecal resection and the others were nonsurgically followed. No cecal resection had residual neoplasia. No patient developed recurrence or pseudomyxoma peritonei (mean follow-up, 4.7 years).
  
  
  CONCLUSIONS
  In patients with LAMNs confined to the appendix, involvement of the appendectomy margin by neoplastic epithelium or acellular mucin does not predict recurrence of disease, even without further surgery. A conservative approach to managing these patients can be justified.
authors: From the Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston (Drs Arnason, Kamionek, and Misdraji); the Division of Anatomical Pathology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, Nova Scotia, Canada (Dr Arnason); the Department of Pathology, University of Massachusetts Memorial Medical Center, Worcester (Dr Yang); and the Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York (Dr Yantiss). Dr Kamionek is now located at the Carolinas Pathology Group, Carolinas Medical Center, Charlotte, North Carolina.
authors: Thomas
authors: T
authors: Arnason
authors: Michal
authors: M
authors: Kamionek
authors: Michelle
authors: M
authors: Yang
authors: Rhonda K
authors: RK
authors: Yantiss
authors: Joseph
authors: J
authors: Misdraji
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology* / Q000601:surgery; D000236:Adenoma / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001062:Appendectomy / Q000379:methods; D001063:Appendiceal Neoplasms / Q000473:pathology* / Q000601:surgery; D001065:Appendix / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018365:Neoplasm, Residual / Q000175:diagnosis; D015203:Reproducibility of Results; D016896:Treatment Outcome