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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.

If you are unable to follow up with the physician, do not report this case until or unless more information becomes available.

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.

Code the specific histology as stated by the pathologist according to the site-specific instructions in the Solid Tumor Rules. When the histology provides a subtype/variant in addition to the HPV histology codes, code the subtype/variant as it is important to capture this histology as in the example provided. the instruction to code the subtype/variant over 8085 or 8086 applies to the following sites: oropharynx, cervix, vagina, vulva, anus, and penis. A note will be added indicatng this in 2025. 

Per 2024 Cancer PathCHART expert pathologist review, morphology codes 8085/3 and/or 8086/3 are valid and applicable to head and neck, oropharynx, cervix, vagina, vulva, fallopian tube, anus, and penis (reference: Cancer PathCHART: Product Downloads and Timelines). Other coding resources will be updated to reflect these changes in 2025.

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).

Assign code 8461/3 for high-grade papillary serous carcinoma.

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).

Use all information available in the medical record. EOD is a combination of the most precise clinical and pathological documentation of the extent of disease as instructed in the EOD 2018 General Instructions, Extent of Disease section.

EOD 2018 General Instructions, General Coding Instructions section advises to use the medical record documentation to assign EOD when there is a discrepancy between the T, N, M information and the documentation in the medical record. When there is doubt that the documentation in the medical record is complete, code the EOD corresponding to the physician staging. A discrepancy can exist within the medical record when the information in the chart is unclear, incomplete, or conflicting, for example, the TNM staging from pathology differs from the medical oncologist’s TNM staging.

In the scenario provided, use the medical oncologist stage information that takes into account imaging and exam findings. Based on the stage cT4 N3b, assign

EOD Primary Tumor: 400

Extensive skin involvement

WITHOUT a stated diagnosis of inflammatory carcinoma

WITH or WITHOUT dermal lymphatic filtration

EOD Regional Nodes: 600

Internal mammary node(s), ipsilateral, clinically apparent

(On imaging or clinical exam)

WITH axillary (level I, II, or III) lymph node(s), ipsilateral including infraclavicular

When there is neoadjuvant therapy followed by surgery, do not record the size from the pathologic specimen. Code the largest size of the tumor prior to neoadjuvant treatment; if unknown code size as 999. We will remove Coding Instruction 12.a.i in the next version of the manual.

In sites other than breast (see Breast Solid Tumor Rules M8/M9), Paget disease with underlying invasive disease is a single primary and the underlying histology is coded. Primary Paget disease of the vulva is uncommon, and we cannot create rules for all possible situations in the Other Sites module. A GYN specific module is in development, and we will look into adding a Paget-related rule. It will differ because Paget in breast is a different situation while Paget in the vulva is always adenocarcinoma.

Paget disease of the vulva is an in-situ adenocarcinoma of vulvar skin with or without an underlying adenocarcinoma (WHO Classification of Female Genital Tumors, 5th ed.). When there is a statement of “underlying” adenocarcinoma, it is a single primary as with Breast Solid Tumor Rule M8.