Data Last Updated: June 9, 2025

NAACCR Item #3960: Histologic Subtype

Item # Length Source of Standard Section Name Year Implemented Version Implemented XML NAACCR ID Parent XML Element
3960 1 SEER Stage/Prognostic Factors 2023 23 histologicSubtype Tumor
Required Status:

NPCR Collect: Required, site specific; when available
CoC Collect: Required, site specific
SEER Collect: Required, site specific
CCCR Collect: Required, site specific; when available

Description
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.
Allowable Values
0, 1, 2, 3, 4
Codes
Code Description
0 Histology is NOT 8480
1 Low-grade appendiceal mucinous neoplasm LAMN
2 High-grade appendiceal mucinous neoplasm HAMN
3 Mucinous Adenocarcinoma/carcinoma<br/> Mucus Adenocarcinoma/carcinoma<br/> Mucoid adenocarcinoma/carcinoma<br/> Colloid adenocarcinoma/carcinoma
4 Other terminology coded to 8480
Blank NA-Diagnosis year is prior to 2023