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The NAACCR Annotated Histology List (AL) serves as an aid to registry software vendors for implementing annual histology changes. This file has been maintained by the Registry Plus team at CDC’s NPCR for several years and reflects modifications to ICD-O-3 implemented by North American cancer registries over time. Although this list is reviewed multiple times prior to posting, there is no guarantee of 100% accuracy. 

As such, the AL is not a substitute for referring to various standard-setter documents and implementation guidelines. In this instance, Medulloblastoma Desmoplastic SHH-activated and TP53-wildtype 9471 is across several resources: the Solid Tumor Rules, Malignant CNS and Peripheral Nerves module in Table 3, column 3  as a subtype/variant of Medulloblastoma NOS 9470; in the CNS WHO 5th Edition BB; and in the WHO IARC ICD-O-3.2 posted to  ICD O 3 Coding Updates (naaccr.org). Although the exact related term of Medulloblastoma, SHH-activated, NOS is not listed, the NAACCR Implementation Guidelines for 2024 recommend checking the 2024 ICD-O-3 Update Table 1 or 2 to determine if the histology is listed. If the histology is not included in the update, then review ICD-O-3.2 and/or Hematopoietic and Lymphoid Database and/or Solid Tumor Rules (MP/H).

The Cancer PathCHART initiative has been undertaken to address gaps such as this between standard setting resources. Having all the standard histology coding resources included in a single all-inclusive database enables alignment of morphology codes & terms included in the CPC*SMVL (Cancer PathCHART Site-Morphology Validation List), Solid Tumors Rules, ICD-O-3 Annual Updates, NAACCR Annotated Histology List as well as the WHO 5th edition Blue Books. Please see Cancer PathCHART - Tumor Site-Morphology Surveillance Standards Initiative for more information on the Cancer PathCHART initiative, and more specifically, see Transitioning the Annotated Histology List to Cancer PathCHART (naaccr.org).

Abstract this case as a single primary. Code as 8044/3 (small cell carcinoma, hypercalcemic type) listed in the Other Sites Solid Tumor Rules, Table 13. Small cell carcinoma, large cell variant, is a subtype of small cell carcinoma, hypercalcemic type. This table does not include all possible histologies.

WHO Classification of Female Genital Tumors, 5th edition, states: Small cell carcinoma of the ovary, hypercalcemic type, is rare, accounting for < 1% of ovarian tumors. Small cell carcinomas, hypercalcemic type, are usually large, with a mean size of 15 cm (range: 6–26 cm). Large cells are present (in varying numbers) in half of these tumors, which are designated “small cell carcinoma, large cell subtype” if the large cells are predominant (which is rare).

Stop at the first rule that applies which is M12. Per note 3: When it is unknown/not documented whether the patient had a recurrence, use date of diagnosis to compute the time interval. This means there are two primaries.

There is a genetic syndrome that causes multiple carcinoid tumors in the GI tract, per our GI expert, and they should be treated as new primaries per M12.

SINQ 20110046 describes a unique situation whereby the subject matter expert felt that the occurrence of multiple tumors was due to an unknown underlying condition driving the proliferation of neuroendocrine cells.

Please understand that AJCC sets the standards for TNM Staging and the Cancer PathCHART (CPC) initiative sets standards for the validity of site and morphology combinations. The statement in the AJCC manual “8240 and 8249 are excluded for topography code C160” means that these two histologies are not staged using the AJCC Staging System. As with numerous other reportable entities that are not staged by AJCC, the case is reportable and a Summary Stage should be assigned. Combinations of C160 with 8240 or 8249 are valid site/histology combinations for registry reporting and should not be discouraged from use if they correspond to the pathologist’s diagnosis. This goes for any other similar note in the AJCC manual. All CPC standards are enforced via the Primary Site, Morphology-Type, Beh ICDO3, 2024 (SEER) N7040 and Histologic Type ICDO3, Primary Site, Date of Diagnosis (NAACCR) N4911 data quality edits. Registrars can also look up the validity of site and morphology combinations using the CPC*Search tool:  https://seer.cancer.gov/cancerpathchart/search/tool/. 

It is important to remember the following.

• ALWAYS code the tumor histology stated by the pathologist/physician
• NEVER change the tumor histology to assign TNM
• Not all tumors or histologies can be staged per TNM
• Cases that cannot be assigned TNM are assigned a summary stage

Report VIN II. The 2024 SEER Manual lists this as a separate diagnosis in the Reportability section under Malignant Histologies 1.a.x. 

The CPC ICD-O-3 Site Morphology Validation Lists (SMVLs) designate all tumor site-morphology combinations that are either valid or impossible as determined for the sites reviewed by the Cancer PathCHART initiative. These lists provide information on the Validity Status of specific tumor site and morphology combinations, similar to the way the ICD-O-3 SEER Site/Histology Validation List used to. However, the CPC SMVLs do not include information on the reportability of specific tumor site and morphology combinations. For tumor reportability, you will continue to use the Excel ICD-O-3.2 spreadsheets posted to the NAACCR ICD-O-3 Coding Updates website: https://www.naaccr.org/icdo3/, and the most recent SEER Manual and federal, state, local, and other standard setters' reportability requirements.

Assign histology as 8072 for non-keratinizing SCC, undifferentiated subtype.

 WHO Classification of Head and Neck Tumors, 5th edition assigns 8072/3 to squamous cell carcinoma, non-keratinizing, NOS in the nasopharynx. As the tumor exhibits a variety of architectural patterns and appearances histologically, they can be further classified as undifferentiated or differentiated subtypes. These subtypes do not change the histology code.

Code SEER Summary Stage 2018 to Localized, Code 1. Per consult with AJCC and noted in the Primary Peritoneal Chapter in AJCC 8th edition, an intraoperative rupture is coded as a surgical spill. 

A capsule rupture is when the capsule ruptures prior to the surgery (Summary Stage Regional, Code 2). 

Report LN II and LN III along with LIN II and LIN III and assign code 8520/2.

WHO Classification of Breast Tumors, 5th edition, lists lobular neoplasia as acceptable, related terminology for lobular carcinoma in situ. 

Sites may be added to certain combinations when indicated by ClinCORE review for Cancer PathCHART. Please note some sites were added in the 2024 update as a result of PathCHART review. A newly-formed Solid Tumor Editorial Board and its subgroups are currently working to evaluate the Solid Tumor Manual and make recommendations on ways to improve the structure and formatting of the manual and its content.

Follow the rules and instructions in the Other Sites STRs when assigning combination histology codes.

Histology Coding Rules

Use the Histology Coding Rules when assigning combination codes.

Coding Histology Information

Use this section that includes the mixed histology (Table 2) and site-specific histology tables (Tables 3-23) for one or more histologies within a single tumor. Do not use this section in place of the Histology Coding Rules.

While site-specific histology tables, based on current WHO Classification of Tumors books, have been added to Other Sites STRs, not all site groups have individual histology tables; coding may require the use of ICD-O and updates. The histology tables in Other Sites STRs include additional coding instructions and notes to assign the correct ICD-O code when appropriate.

The tables are not meant to be all-inclusive; rather they are intended to address difficult coding situations to facilitate the assignment of the correct histology code.

Table 2: Mixed and Combination Codes Instructions

Once you have identified the histology terms and have been instructed to use Table 2 by the Histology Coding Rules, compare the terms in the diagnosis to the terms in Column 1. When the terms match, use the combination code listed in Column 2. Use adenocarcinoma mixed subtypes 8255 as a “last resort” code.