Post-inflammatory mucosal hyperplasia and appendiceal diverticula simulate features of low-grade appendiceal mucinous neoplasms

Abstract A mucocele refers to an appendix that has dilated due to progressive accumulation of mucus within its lumen. Appendiceal mucocele is a rare cause of an acute abdomen. They represent 0.2-0.7% of all appendix specimens. LAMN account for less than 0.3% of appendicectomy specimens. We present a 38 year old man with an acute RIF’s pain who went on to have CT scan which revealed a mucocele of appendix but did not show any features of perforation or pseudomyxoma peritonei. He had a laparoscopic converted to open appendicectomy. The proximal 2 cm of appendix was oedematous but normal calibre. Histology revealed a low grade appendiceal mucinous neoplasm (LAMN) that was completely excised. The mucocele of the appendix was first described by Rokitansky in 1842. Appendix mucocele may come as a consequence of obstructive or inflammatory processes, cystadenomas or cystadenocarcinomas. Appendiceal mucinous neoplasms commonly presents in the sixth decade of life and our patient was much younger in comparison. Several literatures suggest the value of preoperative CT imaging in obtaining diagnosis and also in planning further treatment. Appendicectomy or a right hemicolectomy is treatment of choice based on presence or absence of following factors 1. Perforated mucocele 2. Involvement of the base of the appendix. 3. Positive lymph nodes of mesoappendix and ileocolic. Patients with malignancy or pseudomyxoma peritonei are likely to require cytoreductive surgery, heated intraoperative intraperitoneal chemotherapy, early postoperative intraperitoneal chemotherapy.

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Outcomes of Low-Grade Appendiceal Mucinous Neoplasms with Remote Acellular Mucinous Peritoneal Deposits

Annals of Surgical Oncology ◽

10.1245/s10434-018-7003-7 ◽

2018 ◽

Vol 26 (1) ◽

pp. 118-124 ◽

Cited By ~ 9

Author(s):

Campbell S. Roxburgh ◽

Yaniv M. Fenig ◽

Andrea Cercek ◽

Jinru Shia ◽

Rachel M. Rassam ◽

...

Keyword(s):

Low Grade ◽

Mucinous Neoplasms

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GNAS is frequently mutated in both low-grade and high-grade disseminated appendiceal mucinous neoplasms but does not affect survival

Human Pathology ◽

10.1016/j.humpath.2014.04.018 ◽

2014 ◽

Vol 45 (8) ◽

pp. 1737-1743 ◽

Cited By ~ 41

Author(s):

Aatur D. Singhi ◽

Jon M. Davison ◽

Haroon A. Choudry ◽

James F. Pingpank ◽

Steven A. Ahrendt ◽

...

Keyword(s):

Low Grade ◽

High Grade ◽

Mucinous Neoplasms

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Low-Grade Appendiceal Mucinous Neoplasms: A Single Institution Experience of 64 Cases With Clinical Follow-up and Correlation With the Current (Eighth Edition) AJCC Staging

International Journal of Surgical Pathology ◽

10.1177/1066896919883679 ◽

2019 ◽

Vol 28 (3) ◽

pp. 252-258 ◽

Cited By ~ 2

Author(s):

Mary Wong ◽

Brad Barrows ◽

Alexandra Gangi ◽

Stacey Kim ◽

Richard B. Mertens ◽

...

Keyword(s):

Progressive Disease ◽

Low Grade ◽

Single Institution ◽

Mucinous Neoplasms ◽

Pathologic Staging ◽

Eighth Edition ◽

Ajcc Staging ◽

Disease Free ◽

Histopathologic Features

Background. In this single-institution study, we applied the current (eighth edition) American Joint Committee on Cancer pathologic staging criteria to 64 low-grade mucinous neoplasms of the appendix (LAMNs), examined their histopathologic features, and studied the patients’ clinical outcomes. Design. Sixty-four LAMNs, with a median follow-up of 52 months, were reviewed. Results. The distribution of pathologic stages was pTis (n = 39), pT3 (n = 1), pT4a (n = 5), pT4aM1a (n = 8), and pT4aM1b (n = 11). Recurrence was observed in only 2 patients (both with pT4aM1b disease), one of whom died of disease. All remaining patients were disease-free after a median clinical follow-up of 60 months. Conclusions. Our study confirms that pTis LAMNs have an excellent prognosis and suggests that pT4a and pT4aM1a LAMNs may also have a low risk of developing progressive disease.

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