Citation, DOI, disclosures and article data
Citation:
Di Muzio B, Saber M, Bell D, et al. High-grade appendiceal mucinous neoplasms. Reference article, Radiopaedia.org (Accessed on 06 Jul 2024) https://doi.org/10.53347/rID-54956
High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumors of the appendix showing high-grade cytologic atypia, cf. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on histological grounds and these tumors look the same on imaging. Please, refer to the LAMN article for a detailed conjoined discussion on their imaging findings.
Terminology
Considerable controversy still exists on mucinous neoplasms of the appendix pathologic classification and nomenclature 3. According to a panel of specialist review in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behavior has been proposed, which now includes the “high-grade appendiceal mucinous neoplasm”. The HAMN was proposed to include the lesions that have high-grade atypia and thus cannot be grouped as a LAMN, but also do not have the infiltrative invasion to be characterized as an appendiceal mucinous adenocarcinoma 1,2.
Pathology
Histologically these tumors show high-grade cytologic atypia associated with at least one of the following 1,2:
- loss of the muscularis mucosae
- fibrosis of the submucosa
- rupture of the appendix
- mucin and/or tumoral cells outside the appendix
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1. Carr NJ, Cecil TD, Mohamed F, Sobin LH, Sugarbaker PH, González-Moreno S, Taflampas P, Chapman S, Moran BJ. A Consensus for Classification and Pathologic Reporting of Pseudomyxoma Peritonei and Associated Appendiceal Neoplasia: The Results of the Peritoneal Surface Oncology Group International (PSOGI) Modified Delphi Process. The American journal of surgical pathology. 40 (1): 14-26. doi:10.1097/PAS.0000000000000535 - Pubmed
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2. Leonards LM, Pahwa A, Patel MK, Petersen J, Nguyen MJ, Jude CM. Neoplasms of the Appendix: Pictorial Review with Clinical and Pathologic Correlation. Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (4): 1059-1083. doi:10.1148/rg.2017160150 - Pubmed
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3. Tirumani SH, Fraser-Hill M, Auer R, Shabana W, Walsh C, Lee F, Ryan JG. Mucinous neoplasms of the appendix: a current comprehensive clinicopathologic and imaging review. Cancer imaging : the official publication of the International Cancer Imaging Society. 13: 14-25. doi:10.1102/1470-7330.2013.0003 - Pubmed
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