Prognostic significance of localized extra-appendiceal mucin deposition in appendiceal mucinous neoplasms.
Appendiceal mucinous neoplasms confined to the mucosa are benign, whereas those with disseminated peritoneal mucin deposits often follow an indolent, but malignant, course. Not infrequently, appendiceal mucinous neoplasms are associated with localized periappendiceal mucin deposits, but lack diffuse peritoneal involvement. Mucin deposits in these cases may be acellular or contain neoplastic epithelium (cellular mucin). Although some investigators consider both acellular and cellular periappendiceal mucin to pose no, or minimal, risk for recurrent disease, the biologic importance of localized extra-appendiceal mucin has never been evaluated. We identified 65 patients with appendiceal mucinous neoplasms, all of whom had localized periappendiceal mucin deposits without diffuse peritoneal involvement, and assessed them for the presence of extra-appendiceal epithelium and clinical outcome. Forty-nine (75%) appendices were submitted in total for histologic evaluation. Most (77%) cases showed acellular periappendiceal mucin, but 15 (23%) had scant extra-appendiceal epithelium (range: 1 to 12 cell clusters). Upon follow-up (mean: 48 mo), 2 (4%) patients with acellular periappendiceal mucin developed diffuse peritoneal disease, but neither of these appendices was submitted in total for histologic evaluation. In contrast, 5 of 15 (33%) patients with cellular periappendiceal mucin developed mucinous ascites, including 1 who eventually died of disease (P=0.03). Thus, patients with appendiceal mucinous neoplasms and acellular periappendiceal mucin are unlikely to develop recurrent disease. However, microscopic examination of the entire appendix is necessary, as lesions with extra-appendiceal tumor cells are more likely to progress to disseminated disease and result in death of the patient, even if the mucin is paucicellular and confined to the periappendiceal region.
Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA. rhy2001@med.cornell.edu
Rhonda K
RK
Yantiss
Jinru
J
Shia
David S
DS
Klimstra
Hejin P
HP
Hahn
Robert D
RD
Odze
Joseph
J
Misdraji
D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000378:metabolism / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism*; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011379:Prognosis
D009077:Mucins