# PSOGI consensus for classification and pathological reporting of pseudomyxoma peritonei and associated appendiceal neoplasia

Source: https://onco.cc/key-papers/paper-psogi-pseudomyxoma-appendiceal-classification-am-j-surg-pathol-2016/  
OnCo record `paper-psogi-pseudomyxoma-appendiceal-classification-am-j-surg-pathol-2016` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Pathologists from around the world agreed on what to call the mucinous tumours of the appendix and the jelly-like peritoneal disease they cause, replacing a tangle of older names with low-grade appendiceal mucinous neoplasm, high-grade neoplasm and adenocarcinoma.

## Summary

Modified Delphi consensus of the Peritoneal Surface Oncology Group International defining terminology for appendiceal mucinous neoplasms (low-grade appendiceal mucinous neoplasm or LAMN, high-grade appendiceal mucinous neoplasm, and mucinous adenocarcinoma with well, moderately or poorly differentiated grades, the last including signet ring cells) and for pseudomyxoma peritonei (acellular mucin, low-grade, high-grade, and high-grade with signet ring cells).

The scheme was adopted by the WHO 2019 digestive classification and underpins prognosis and the decision to offer cytoreductive surgery with HIPEC.

## Fields

- Kind: Key paper
- Last checked: 2026-09-18
- Journal: American Journal of Surgical Pathology
- Year: 2016
- DOI: 10.1097/PAS.0000000000000535
- Authors: Carr NJ, Cecil TD, Mohamed F, et al.
- What it means: Whether an appendiceal tumour is called LAMN or adenocarcinoma, and whether peritoneal disease is graded low or high, decides prognosis and treatment; this paper set those names.
- Caveats: Consensus of experts rather than outcome data.; Terms such as 'mucinous carcinoma peritonei' in older papers do not map cleanly onto the new grades.

## Sources

- Am J Surg Pathol 2016: https://doi.org/10.1097/PAS.0000000000000535
- PubMed: https://pubmed.ncbi.nlm.nih.gov/26492181/

## Connected records

- cancers: [Appendiceal adenocarcinoma (mucinous and non-mucinous, including signet ring cell)](https://onco.cc/cancers/appendiceal-adenocarcinoma/), [Low-grade appendiceal mucinous neoplasm and pseudomyxoma peritonei](https://onco.cc/cancers/low-grade-appendiceal-mucinous-neoplasm/)

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