NAACCR Item #3960: Histologic Subtype

Item # Length Source of Standard Year Implemented Version Implemented Year Retired Version Retired
3,960 1 SEER 2023 23

NAACCR XML: Tumor.histologicSubtype


Histology code for appendiceal tumors (8480) is defined as “Mucinous Adenocarcinoma (in situ or invasive).” In the AJCC 8th chapter for Appendix-Carcinoma, there are also low-grade appendiceal mucinous neoplasm (LAMN) and high-grade appendiceal mucinous neoplasm (HAMN) diagnoses that are assigned the same histology.

Due to the different natures of these histologies, there is interest in tracking these different types of tumors. With the current histology codes, a distinction cannot be made. A histology subtype data item is needed.


0Histology is NOT 8480
1Low-grade appendiceal mucinous neoplasm LAMN
2High-grade appendiceal mucinous neoplasm HAMN
3Mucinous Adenocarcinoma/carcinoma
Mucus Adenocarcinoma/carcinoma
Mucoid adenocarcinoma/carcinoma
Colloid adenocarcinoma/carcinoma
4Other terminology coded to 8480
BlankNA-Diagnosis year is prior to 2023