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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.   

Do not include the disease in the sequencing if the original hematolymphoid disease was not reportable at time of diagnosis.

The 2025 SEER Manual Sequence Number--Central Coding Instruction 1.a advises: A ‘reportable’ primary refers to the site/histology/behavior of the tumor and the years when reporting was required. Review of the reportability requirements in effect during the diagnosis year will be needed.

Do not report superficial CD34-positive fibroblastic tumor (8810/1) of the thigh.

WHO Classification of Soft Tissue and Bone Tumors, 5th ed., defines superficial CD34-positive fibroblastic tumor as a distinctive low-grade neoplasm of the skin and subcutis, most frequently occurring in the lower extremities, especially thigh, followed by arm, buttock, shoulder, and rarely, vulva.

Assign code 01 (White) for Race 1 when described as Indigenous-Latino/a or Indigenous-Latinx. Indigenous-Latinx is an umbrella term for Indigenous migrants to the United States from Latin America including South and Central America, the Caribbean, and Mexico (for example, Maya, Mixteco, Purépecha, Taino, Zapoteco, etc.). Latin America is listed in Appendix D of the 2025 SEER Manual as White.

Assign code 6 (Spanish, NOS; Hispanic, NOS; Latino, NOS) for Spanish Surname or Origin for Indigenous-Latino/a or Indigenous-Latinx in the absence of more specific information. Code 6 description includes the statement, There is evidence, other than surname or birth surname (maiden name), that the person is Hispanic but he/she cannot be assigned to any of the categories 1-5.

Assign code 03 (American Indian or Alaska Native) when described as First Nations. First Nations usually refers to Indigenous peoples for ethnic groups who are the original or earliest known inhabitants of an area. The term ‘First Nations’ can be applied to individuals, but technically refers only to those who have Indian status under Canadian law as part of a recognized community. Within Canada, the term First Nations is generally used for Indigenous peoples other than Inuit and Métis. Outside Canada, the term can refer to Indigenous Australians, U.S. tribes within the Pacific Northwest, as well as supporters of the Cascadian independence movement. 

Code Neoadjuvant Therapy--Treatment Effect using the surgical pathology report only. Carefully review the pathology report gross description and comments to assist with assignment of codes.

Review of neoadjuvant therapy data items is currently underway.

High grade squamous dysplasia (8077/2) is reportable for head and neck sites for cases diagnosed as of 01/01/2021. High grade glandular intraepithelial neoplasia / glandular intraepithelial neoplasia grade III (8148/2) and high grade squamous intraepithelial neoplasia / squamous intraepithelial neoplasia grade III (8077/2) are reportable for head and neck sites for cases diagnosed as of 01/01/2001. Refer to other standard setters’ criteria for reportability as appropriate.

Do not use the NME size from magnetic resonance imaging (MRI) to code tumor size when both tumor size and NME size are stated or if NME is the only size available. The size of the solid tumor mass takes priority over the size of the NME when provided separately and the NME is larger.

The American College of Radiology, Breast Imaging Reporting and Data System (BI-RADS) defines NME as an area of enhancement on MRI that does not belong to a 3D mass or have distinct features of a mass. It is a separate descriptor from size that includes modifiers describing enhancement patterns with a specific MRI pattern.

Do not code as a treatment. Record the cessation of immunosuppressive drug treatment in text to explain the patient’s change in disease status.

Reportability for EIN became effective in 2021. 

1. Do not report atypical glandular epithelium. Atypical glandular epithelium, also referred to as atypical glandular cells (AGC), refers to abnormal looking cells that may be found in the tissue lining the inside of the endometrium or the cervix. While not malignant (in situ or invasive), they can be associated with a range of lesions in the female reproductive system.

2. Do not report isthmic-type mucosa with focal severe atypia. The NCI data dictionary defines atypia as an abnormality in cells in tissue. Report the case when further defined as atypical hyperplasia.

3. Do not report simple hyperplasia without atypia. WHO Classification of Tumors online, Female Genital Tumors (5th ed.), defines endometrial hyperplasia without atypia as a proliferation of endometrial glands of irregular size and shape without significant atypia. There is no ICD-O code for this term. Simple endometrial hyperplasia without atypia is an acceptable related term for endometrial hyperplasia without atypia. Pathology has priority over a physician statement.

4. Report EIN/CAH or focal EIN/CAH (8380/2) based on the biopsy. WHO Classification of Tumors online, Female Genital Tumors (5th ed.), defines EAH/EIN as a simultaneous change of epithelial cytology and an increased number of endometrial glands in a defined region. The preferred term is atypical hyperplasia of the endometrium; terms not recommended include complex atypical endometrial hyperplasia; simple atypical endometrial hyperplasia; endometrial intraepithelial neoplasia.

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.