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Low grade appendiceal mucinous neoplasm (LAMN) is not reportable in 2018. See page 6, https://20tqtx36s1la18rvn82wcmpn-wpengine.netdna-ssl.com/wp-content/uploads/2018/02/2018-ICD-O-3-Coding-Table-Alpha-order-.pdf. Use cancer registry reportability instructions to determine reportability. Do not use the AJCC TNM manual to determine reportability.

For cases diagnosed 2007 or later:

This is a single primary using rule M2; a single tumor is always a single primary.

The histology code for this case is 8260/3 [Papillary carcinoma of thyroid]. Begin with Histology Coding rule H8. Stop at rule H17 and code the histology with the numerically higher ICD-O-3 code.

Updated May 2026

Abstract the diffuse large B-cell lymphoma (Richter transformation) as a second primary per Rule M10. Rule M10 states to abstract as multiple primaries when a neoplasm is originally diagnosed as a chronic neoplasm (CLL) AND there is a second diagnosis of an acute neoplasm (the diffuse large B-cell lymphoma (Richter transformation)) after the initial clinical workup for the chronic neoplasm is completed.

"Richter transformation," also known as "Richter syndrome," is a term that indicates CLL has transformed to DLBCL. Richter syndrome is listed under the Alternate Names section in the Heme DB for DLBCL (9680/3).

If there is no further information about where the cancer originated, assign C220. Use ICD-O-3 as the source for coding topography. The topography code associated with combined hepatocellular and cholangiocarcinoma (8180/3) is C220 when there is no other information available, according to ICD-O-3.

Many of these terms are not specified in the codes and definitions in ICD-10-CM. This is because ICD-10-CM does not have the same granularity as ICD-O-3.2. There are a few sites where intraepithelial neoplasia II and/or III are mentioned.

Even though ICD-O-3.2 classifies these as /2 (in-situ), for the intraepithelial neoplasia that are listed in ICD-10-CM, Grade II is designated as benign, while Grade III is designated as in-situ. It is not clear if medical coding will change the Grade II to an in-situ code.

All the in-situ codes (except cervix) are included in the casefinding list. Grade III is included with the in-situ codes; however, there is no guarantee that medical coders will code them as in situ. High grades are coded as in-situ in ICD-10-CM.

For those where there is no specific intraepithelial neoplasia code, the benign codes will cover any benign lesion for that site. This would make for a lot of review using the codes for casefinding. Most of the benign codes were removed from the casefinding list a couple of years ago to make it more manageable. 

Use the casefinding list as a guide for these neoplasias. It is not the most definitive source due to the lack of specificity of ICD-10-CM. It is not possible to map every single histology to a specific code. It is also not known how medical coders across the U.S. are coding these neoplasias. For that reason, pathology should remain the foremost casefinding resource used.

The casefinding team will need to review the prepared list below and determine what codes to add. Any updates will be incorporated in the FY2025 updates (October 2024.)

For tumors diagnosed prior to 2007:

Unless it is stated to be a RECURRENT or METASTATIC melanoma, record each melanoma as a separate primary when:

1. The occurrences are more than two months apart.

2. The fourth digit of the ICD-O topography code for skin [C44._] is different .

3. The first three digits of ICD-O-3 morphology code are different.

4. An in situ melanoma is followed by an invasive melanoma.

For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.