Appendix
General
WHO classification
Author: Raul S. Gonzalez, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 10 December 2020
Last staff update: 22 February 2024
Copyright: 2020-2024, PathologyOutlines.com, Inc.
PubMed Search: WHO classification appendix
Cite this page: Gonzalez RS. WHO classification. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/appendixwhoclassification.html. Accessed April 18th, 2024.
Definition / general
- WHO classification of tumors of the appendix
- Currently on 5th edition, published in 2019
- Based on histologic appearance, not molecular characteristics
WHO (2019)
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Epithelial tumors ICD-O codes
- Hyperplastic polyp
- Sessile serrated lesion without dysplasia
- Serrated dysplasia, low grade 8213/0
- Serrated dysplasia, high grade 8213/2
- Low grade appendiceal mucinous neoplasm 8480/1
- High grade appendiceal mucinous neoplasm 8480/2
- Adenocarcinoma, NOS 8140/3
- Mucinous adenocarcinoma 8480/3
- Signet ring cell adenocarcinoma 8490/3
- Carcinoma, undifferentiated, NOS 8020/3
- Goblet cell adenocarcinoma 8243/3
- Neuroendocrine tumor, NOS 8240/3
- Neuroendocrine tumor, grade 1 8240/3
- Neuroendocrine tumor, grade 2 8249/3
- Neuroendocrine tumor, grade 3 8249/3
- L cell tumor 8152/3
- Glucagon-like peptide producing tumor 8152/3
- PP / PYY producing tumor 8152/3
- Enterochromaffin cell carcinoid 8241/3
- Serotonin producing carcinoid 8241/3
- Neuroendocrine carcinoma, NOS 8246/3
- Large cell neuroendocrine carcinoma 8013/3
- Small cell neuroendocrine carcinoma 8041/3
- Mixed neuroendocrine - nonneuroendocrine neoplasm (MiNEN) 8154/3
