Histology Subtype
Notes
**Note 1:** This SSDI is effective for diagnosis years 2023+.
+ For cases diagnosed 2018-2022, leave this SSDI blank
**Note 2:** Use the Solid Tumor Rules to determine histology prior to coding this SSDI.
**Note 3:** Histology 8480/2 or 8480/3 have multiple definitions that are collected in this histology. This data item is used to further identify specific subtypes for histology code 8480/2 or 8480/3.
*Examples:*
1. Appendix: Disseminated peritoneal adenomucinous/low grade mucinous carcinoma peritonei. Final diagnosis: Low grade appendiceal mucinous neoplasm
+ Code 1: This is a low grade mucinous (appendiceal) carcinoma (8480/3), which is LAMN. The peritoneal adenomucinous/low grade mucinous carcinoma peritonei is describing metastatic disease and not the histology
2. Appendix: Low grade (well diff) appendiceal adenocarcinoma
+ Code 0: This is an adenocarcinoma (8140/3), the low grade (well diff) is describing the grade and not the histology
3. Appendix, appendectomy: Low grade appendiceal mucinous neoplasm (LAMN) with focal high grade mucinous neoplasm.
+ Code 1: Based on the Solid Tumor Rules, the “focal” would be ignored and this would be a LAMN.
4. Appendectomy: Mucinous adenocarcinoma of the appendix
+ Code 3: Mucinous adenocarcinoma is the preferred terminology for histology code 8480/3. Since there is no mention of “low grade” or “high grade”, this would not be LAMN or HAMN
5. Appendix: Mucinous (colloid) adenocarcinoma
+ Code 3: Colloid adenocarcinoma is an alternate name for 8480/3
Metadata
SSDI 2023–
| 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
Mucus Adenocarcinoma/carcinoma
Mucoid adenocarcinoma/carcinoma
Colloid adenocarcinoma/carcinoma |
| 4 |
Other terminology coded to 8480 |
| <BLANK> |
NA-Diagnosis year is prior to 2023 |
