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For cases diagnosed 2025 and later: Assign behavior /1 for solitary fibrous tumor unless stated to be malignant.

A review by the Cancer PathCHART expert neuropathologists found behavior code /0 is incorrect and both solitary fibrous tumor grade 1 and grade 2 are coded as 8815/1. WHO Classification of Central Nervous System Tumors, 5th edition, assigns behavior as /1 and no longer recommends terms solitary fibrous tumor/hemagiopericytoma and hemagiopericytoma. The STR table is correct. Future updates to ICD-O should reflect this behavior.

WHO Classification of Tumours, Central Nervous System Tumours, 5th ed. was reviewed by the CPC expert pathologists for implementation for cases diagnosed January 1, 2025. 

Reminder: Comparing the CPC Validity Status included in the 2024 CPC*Search to that included in the 2025 SMVL (that table that drives the edits) is incorrect. CNS Tumors were not reviewed for 2024 implementation, they were reviewed for 2025 implementation. There will be a 2025 CPC*Search and a /1 will be designated as a Valid.   

Code Primary Site to C480 (retroperitoneum). 

Endometrial tissue may "break away” from the uterus and implant throughout the pelvic and abdominal cavities. This can occur in patients who suffer from endometriosis. This tissue remains behind when surgical removal of the uterus is done. Common sites of implantation are colon, peritoneum, retroperitoneum, and bladder. These cells may become malignant. When the uterus is no longer present (patient had surgical removal), code the site where the carcinoma was identified.

The site-morphology combination of C480 and 8380/3 was designated as an unlikely site-morphology combination by the Cancer PathCHART expert pathologist review, as this is a rare type of tumor. Assign a value of 1 in the Over-ride Site/Type [2030] data item in order to pass the Primary Site, Morphology-Type, Beh ICDO3, 2024 (SEER) edit.

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 DLBCL (9680/3) as supported by the WHO Classification of Hematolymphoid Tumors, 5th edition. It is consistent with how it would have been coded in the 4th edition. The Heme Manual and Database currently are based on the 4th edition. Physicians are using the 5th edition blue book, whereas the cancer registry field is not yet at this time.

Regarding the Heme Manual and Database, this type of scenario is not covered because it is part of the 5th edition WHO Blue Book. The database cannot be updated until the 5th edition is approved for implementation (2026).

Report these high grade dysplasia of the following organs as stated below.

Stomach: Assign code 8148/2 glandular intraepithelial neoplasia, high grade using the Other Sites Solid Tumor Rules, Table 6: Stomach Histologies and as described in the WHO Classification of Digestive Tumors, 5th edition.

Small intestine and Esophagus: Assign code 8148/2 glandular intraepithelial neoplasia, high grade, using the Other Sites Solid Tumor Rules, Other Sites Histology Rules, Rule H4/H26. The following note is listed for both of these rules.

Note: This list may not include all reportable neoplasms for 8148/2. See SEER Program Coding and Staging Manual or STORE manual for reportable neoplasms

The Other Sites Solid Tumor Rules, Table 5: Esophagus Histologies and Table 7: Small Intestine and Ampulla of Vater Histologies will be updated to reflect this code as time permits.

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.

The correct term is diffuse leptomeningeal glioneuronal tumor listed as a synonym in Column 2. 

We will add the term diffuse in Note 2, Column 1 with the 2025 updates. In the meantime, you can add "diffuse" to your pdf version until the update is published.

Report this case of leukemia cutis and code to bone marrow (C421) and leukemia NOS (9800/3) based on the information provided. Update the abstract if new information becomes available.

Leukemia cutis is the rare infiltration of neoplastic leukocytes into the epidermis, dermis, or subcutis from an existing leukemia that results in clinically identifiable cutaneous lesions. Leukemia cutis may precede, follow, or occur concurrently with the diagnosis of systemic leukemia. It is an advanced phase of the leukemia having a poor prognosis that also strongly correlates with additional sites of extramedullary involvement. This can alter the appropriate treatment regimen for a patient. It is a type of "metastasis" or spread of the leukemia cells. The "conventional" definition for leukemia cutis is the infiltration of skin from a bone marrow primary. It is most often diagnosed via skin biopsy—punch, shave, etc., utilizing IHC/biomarker testing and is commonly associated with CMML and acute myeloid leukemia (AML). As such, it a reportable condition especially when preceding a confirmed systemic leukemia diagnosis. In this situation, the diagnosis date would be the date of the positive leukemia cutis skin bx—punch, shave, etc. The case should be coded to C421; 9800/3 Leukemia NOS until the official systemic leukemia diagnosis is rendered. If possible, follow back should be conducted to determine the specific systemic leukemia histology (CMML; AML) and the treatment received. If the leukemia cutis follows or occurs concurrently with the diagnosis of a systemic leukemia, it is NOT a separate primary but merely an advanced stage of the systemic leukemia diagnosis.

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

Assign code 8020/3 when the histologic type specifically includes the term of poorly differentiated, dedifferentiated, undifferentiated, or anaplastic undifferentiated carcinoma along with carcinoma as terms vary depending on the primary site. When the term poorly differentiated is included in the grade section only of the pathology report or only mentions poorly differentiated carcinoma without further substantiation from a pathology report as in examples 1 and 2, do not use code 8020/3.

The histology code 8020/3 and terms may be used for selected primary sites as included in the Solid Tumor Rules, WHO Classification of Tumors series (latest versions), and the Site/Morphology Validation List including

Nasal cavity

Nasopharynx

Salivary glands

Urinary sites

Colon, rectosigmoid, rectum

Esophagus

Stomach

Gallbladder and extrahepatic bile duct

Pancreas

Thyroid

Ovary

Uterine corpus

Vagina

Uterine cervix (also referred to as unclassifiable in WHO Classification of Female Genital Tumors, 5th ed.)

For sites other than those listed, if the diagnosis is poorly differentiated carcinoma, code 8010/3 and poorly differentiated in the grade field.