The following changes were included in the 2026 Update of the Solid Tumor Rules. This is a document containing changes only. Do not use in place of the Solid Tumor Rules.

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Changes across all site modules

Equivalent Terms and Definitions section was renamed to "Site-group Instructions" throughout.

All "new for 2024" or previous years sections were removed.

Introduction

  • Note about using the MP/H rules versus STR deleted

Equivalent or Equal Terms

  • Terms that were duplicated in histology tables were removed
  • "Adenocarcinoma; carcinoma"
    • Examples updated; negative example added

Histology Tables

  • Notes about only using the code when the exact term is listed deleted
  • Tables converted from 3 columns to 2 columns; column references updated throughout
  • NOS synonyms previously located in column two added to column 1 as bullets
  • Table headers updated
  • Synonyms denoted by bullets and no histology code
  • Subtypes/variants denoted by bullets with a histology code
  • Subtypes/variants and synonyms grouped by behavior and are alphabetized
  • Behavior codes moved to parentheses
  • In-table notes converted to footnotes
  • Table instructions updated to reflect changes
  • Removed asterisks
  • Removed all in-table notes explaining NOS and subtypes
  • Removed outdated or unnecessary notes

Multiple Primary Rules

  • Removed superscript "i" and "ii" from all multiple primary rules along with the associated notes.
  • Note updated to "Metastatic tumors are not included when determining how many tumors are present."

Priority for Using Documentation to Assign Histology

Exception to coding histology prior to neoadjuvant therapy was updated.

"Coding Histology" section

  • Examples removed from item B under Ambiguous Terminology
  • Statement added: "See the Ambiguous Terminology section of the General Instructions for instructions and examples on when ambiguous terms and definitive terms may be used to assign histology."
  • List of ambiguous terms replaced with new table: List of Ambiguous Terminology
    • Notes added below the table with information about terms that were previously considered ambiguous terms, but are now considered definitive terms.
  • New table added: List of Definitive Terminology

General Instructions

The General Instructions underwent some restructuring. Most of the changes were reformatting and clarifications. Some sections were removed and others were moved to a different location. Below you will find an accounting of the changes.

Annual Updates

  • Moved into section titled Diagnosis Years for Which the Solid Tumor Rules Should be Used

Solid Tumor Rules Site-groups by Diagnosis Year

  • Renamed Diagnosis Years for Which the Solid Tumor Rules Should be Used
  • Added information from Annual Updates Section
  • Added an example

Purpose and Structure of the Solid Tumor Rules

  • New section describing the structure of the Solid Tumor Rules including a diagram showing the various components of the Solid Tumor Manual and how they are related.

Submitting Questions

  • Moved to the end of the General Instructions

General or Equivalent Terms

  • Reformatted and relocated to just before the Definitions section

How to Navigate the Solid Tumor Rules

  • Deleted the entire section (it provided instructions on navigating a PDF.)

How to Use the Solid Tumor Rules

  • Deleted the entire section; instructions placed in the Purpose and Structure of the Solid Tumor Rules section

How to Use the Equivalent Terms and Definitions

  • Deleted the entire section; instructions placed in the Purpose and Structure of the Solid Tumor Rules section

Multiple Primary Rules Do NOT Apply to Tumors Described as Metastases

  • Deleted the entire section; instructions placed with each set of site-group "M" rules

How to Use the Multiple Primary Rules

  • Reformatted and added examples

Timing Rules

  • Renamed to Timing Rules for Metachronous Tumors Arising in the Same Site
  • Updated instructions for better clarity

Histologic Type ICD-O-3

  • Moved to the end just ahead of the Important Information for Coding Histologic Type for Cases Diagnosed 1/1/2018 and Forward section

Important Information for Coding Histologic Type for Cases Diagnosed 1/1/2018 and Forward

  • Moved to the end just ahead of the Cancer PathCHART Site-Morphology Combinations Standards section

Cancer PathCHART Site-Morphology Combination Standards

  • Moved to the end just ahead of the Submitting Questions section

How to Use the Histology Rules

  • Reformated and moved information from the previous Priority Order for Using Documentation to Code Histology section
  • Move instructions about ambiguous terminology to its own section

How to Use Ambiguous Terminology to Code Histology

  • Added new list of definitive terms that were previously on the ambiguous terminology list
  • Updated the list of ambiguous terminology
  • Added examples to help with coding histology

Definitions

  • Deleted some terms
  • Added a link to the SEER Glossary for registrars
  • Added STR Module, STR Section, and STR Site-group with a link to the STR Structure
  • Added a definition for the Matrix Rule
  • Added a definition for metachronous

Breast

Introduction

  • Note regarding DCIS: text updated to "Code the grade per the instructions in the Grade Manual."

Equivalent or Equal Terms

  • Deleted "Carcinoma; adenocarcinoma" listing

Table 1: Primary Site Codes

  • Footnotes 2 and 3 updated

Table 2: Histology Combination Codes

  • Instructions > Note 2: Deleted "(both components are invasive)"
  • 8522 row: Revamped for clarity and simplicity (coding rules unchanged)
  • 8526 row: Note removed (was irrelevant): "Do not use combination code for duct with lobular differentiation. This is a synonym for carcinoma NST."

Table 3: Specific Histologies, NOS, and Subtype/Variants

  • Updated Note 3
  • Row added: "Mucinous cystadenocarcinoma 8470"
  • "Neuroendocrine tumor NOS 8240 (/3)" row:
    • Synonyms deleted:
      • Neuroendocrine carcinoma, low grade
      • Neuroendocrine carcinoma, well differentiated
      • Carcinoid of breast
  • Neuroendocrine carcinoma NOS 8246 (/3)" row:
    • Synonym deleted:
      • Poorly differentiated neuroendocrine carcinoma
    • "Large cell neuroendocrine carcinoma 8013 (/3)":
      • Synonym deleted:
        • Large cell carcinoma

Multiple Primary Rules

  • Note 1 (before "Unknown if Single or Multiple Tumors" module)
    • Edited first sentence for clarity
  • M Rule: "Abstract multiple primaries when the patient has a subsequent tumor after being clinically disease-free for greater than five years"
    • Replaced "NED" with "WNL" in Note 2
  • M Rule deleted: "Abstract a single primary when there are multiple tumors of carcinoma NST/duct and lobular." Remaining rules re-numbered.
  • M Rule: "Abstract a single primary when none of the previous rules apply."
    • Updated example for clarity.

Priority for Using Documentation to Assign Histology

  • Entire section moved above "Coding Histology" section to be consistent with other site-groups.

Histology Coding Rules

  • "Coding Histology" section:
    • Switched order with "Priority Order for Using Documentation to Identify Histology" section
    • Existing notes moved to beginning of section:
      • Note regarding differentiation and features
      • Note regarding apocrine carcinoma
  • H Rule: "Code the invasive histology when there are both invasive and in situ histologies."
    • Exception deleted
  • H Rule deleted: "Code 8522 when carcinoma NST and lobular are present in multiple tumors." Remaining rules renumbered.

Colon

Introduction

  • Note 7 revised. Background information related to dysplasia removed.

Equivalent or Equal Terms

  • "Polyp; adenoma; polyp NOS; adenomatous polyp"
    • Deleted Notes 1-3 under polyp equivalent terms

Table 1: Specific Histologies, NOS, and Subtype/Variants

  • Adenocarcinoma row: Both Subtypes/variants 8480 were combined into one entry

Table 2: Histologies Not Reportable for Colon, Rectosigmoid and Rectum

  • Updated description of columns in table 2
  • Moved synonyms (column 2) and subtypes/variants (column 3) into column 1. Synonyms are bulleted under the NOS code without a histology code. The subtype variants are bulleted under the NOS code with a histology and behavior code.
  • Reason not reportable moved to column 2.
  • Removed notes and asterisks from table and converted them to footnotes.

Table 3: Primary Site Codes

  • Added Table 3

Histology Rules

  • H Rule: "Code invasive mucinous adenocarcinoma 8480 when the diagnosis is any of the following…"
    • Added Colloid adenocarcinoma to list of terms assigned to 8480
  • H Rule: "Code adenocarcinoma in familial adenomatous polyposis (FAP) 8220 when clinical history says the patient has familial adenomatous polyposis…"
    • Added “adenomatous” to “Familial adenomatous polyposis”

Head and Neck

Introduction

Introduction section was deleted.

Table Index

  • Rows added:
    • "Table 11: List of Ambiguous Terminology"
    • "Table 12: List of Definitive Terminology"

Table 1: Tumors of Nasal Cavity, Paranasal Sinuses and Skull base

  • "Adenocarcinoma 8140" row:
    • Synonym added: "Renal cell-like sinonasal adenocarcinoma" with footnote
    • Subtype/Variant added: "HPV-related multiphenotypic sinonasal carcinoma 8483 (/3)" with footnote (moved from its own row)
  • Row deleted: "HPV-related multiphenotypic sinonasal carcinoma 8483 (/3)" (moved to adenocarcinoma NOS)
  • "Malignant peripheral nerve sheath tumor 9540 (/3)" row:
    • Subtype/variant deleted and footnote added to column 1: "Malignant neurilemoma/malignant schwannoma 9560/3"
  • "Olfactory neuroblastoma 9522 (/3)" row:
    • All subtypes/variants removed and added as synonyms of 9522
  • "Sarcoma 8800/3" row:
    • (correction) "Spindle cell rhabdomyosarcoma 8912 (/3)" moved to be indented under 8900
  • "Small cell carcinoma, intermediate 8044" row:
    • Column 1 term updated
    • Synonyms added with footnote:
      • SMARCA4-deficent sinonasal carcinoma
      • SMARCB1-deficient sinonasal carcinoma
      • SMARCB1-deficient sinonasal adenocarcinoma
  • "Squamous cell carcinoma 8070" row:
    • SCC NOS synonym "Conventional squamous cell carcinoma NOS" moved to be a synonym of "Keratinizing squamous cell carcinoma NOS"
    • Synonyms added to "HPV-associated squamous cell carcinoma 8085":
      • "Squamous cell carcinoma, HPV-mediated (p16+)"
      • "Squamous cell carcinoma, HPV-positive"
      • "Squamous cell carcinoma, HPV-related"
    • Synonyms added to "HPV-independent squamous cell carcinoma 8086":
      • "Squamous cell carcinoma, HPV-negative"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 2: Tumors of Nasopharynx

  • Synonyms added to "Squamous cell carcinoma 8070" row:
    • "Epidermoid carcinoma"
    • "Squamous carcinoma"
    • "Squamous cell carcinoma"
    • "Squamous cell epithelioma"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 3: Tumors of Pyriform Sinus, Hypopharynx, Larynx, Trachea, and Parapharyngeal Space

  • "Chondrosarcoma 9220 (/3)" row: "Chondrosarcoma, grade 1 9222 (/3)"
    • Footnote clarified
  • Row added: "Neuroendocrine carcinoma 8246 (/3)"
  • "Neuroendocrine tumor NOS 8240 (/3)" row:
    • Synonym deleted: "Well-differentiated neuroendocrine carcinoma"
    • Subtypes/variants moved to 8246 row:
      • "Large cell neuroendocrine carcinoma 8013 (/3)"
      • "Small cell neuroendocrine carcinoma 8041 (/3)"
    • "Neuroendocrine tumor grade 2 8249 (/3)":
      • Synonym deleted: "moderately differentiated neuroendocrine carcinoma"
      • Synonym added: "Neuroendocrine tumor grade 3" with footnote
  • "Squamous cell carcinoma 8070" row:
    • SCC NOS synonym "Conventional squamous cell carcinoma NOS" moved to be a synonym of "Keratinizing squamous cell carcinoma NOS"
    • Synonyms added:
      • "Squamous carcinoma"
      • "Squamous cell epithelioma"
    • Footnote added to "Non-keratinizing squamous cell carcinoma 8072"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 4: Tumors of Oral Cavity and Mobile Tongue

  • Lip primary sites (C000 – C009) added.
  • C051 Soft palate and C052 Uvula removed from Table 4 (moved to Table 5)
  • Note following site code list updated: "Use Table 6 Tumors of the Salivary Glands to assign histology."
  • Row deleted: "Adenosquamous carcinoma 8560" (moved to 8070 row)
  • "Squamous cell carcinoma 8070 row":
    • Synonym added to "Squamous cell carcinoma 8070" row:
      • "Squamous carcinoma"
      • "Epidermoid carcinoma"
      • "Squamous cell epithelioma"
      • "High-grade intraepithelial squamous lesions (/2)"
    • Subtype/variants added:
      • "Adenosquamous carcinoma 8560" (moved from its own row)
      • "HPV-associated oral epithelial dysplasia, high grade 8085 (/2)"
    • Synonym added to "Verrucous squamous cell carcinoma 8051": "Carcinoma cuniculatum"
    • SCC NOS synonym "Conventional squamous cell carcinoma NOS" moved to be a synonym of "Keratinizing squamous cell carcinoma NOS"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 5: Tumors of the Oropharynx, Base of Tongue, Tonsils, Adenoids

  • Example 2 added to Instructions.
  • C051 Soft palate and C052 Uvula removed from Table 4 (moved to Table 5)
  • "Squamous cell carcinoma 8070" row:
    • Synonyms added:
      • "Epidermoid carcinoma"
      • "Squamous carcinoma"
      • "Squamous cell carcinoma"
      • "Squamous cell epithelioma"
    • SCC NOS synonym "Conventional squamous cell carcinoma NOS" moved to be a synonym of "Keratinizing squamous cell carcinoma NOS"
    • Synonyms added to "Squamous cell carcinoma HPV-negative 8086":
      • "HPV-independent squamous cell carcinoma"
      • "Non-keratinizing squamous cell carcinoma, HPV-negative"
    • Footnotes updated for consistency
    • Synonyms added to "Squamous cell carcinoma HPV-positive 8085":
      • "HPV-associated squamous cell carcinoma"
      • "Keratinizing squamous cell carcinoma, HPV-positive"
      • "Squamous cell carcinoma, HPV-mediated (p16+)"
      • "Squamous cell carcinoma, HPV-related"
    • Synonym added to "Verrucous squamous cell carcinoma 8051": "Carcinoma cuniculatum"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 6: Tumors of Salivary Glands

  • Row deleted: "Oncocytic carcinoma 8290" and synonyms (inadvertently appeared twice in the table)
  • "Adenocarcinoma 8140" row:
    • Synonym added to "Carcinoma ex-pleomorphic adenoma 8941 (/3)": "Intracapsular carcinoma ex-pleomorphic adenoma (/2)"
    • Subtype/variant added: "Sclerosing microcystic adenocarcinoma 8407"
    • Subtype/variants removed:
      • "Papillary cystadenocarcinoma 8450"
      • "Polymorphous adenocarcinoma (PAC)/ Polymorphous low-grade adenocarcinoma /Terminal duct carcinoma 8525" (inadvertently appeared twice in the table)
  • "Polymorphous adenocarcinoma 8525" row:
    • Synonyms added:
      • Cribriform polymorphous adenocarcinoma
      • PAC
      • Polymorphous low-grade adenocarcinoma
      • Terminal duct carcinoma
  • "Salivary duct carcinoma 8500" row:
    • "Oncocytic salivary duct carcinoma 8290 (/3)": Synonyms added:
      • Malignant oncocytoma
      • Oncocytic carcinoma
      • Oncocytic adenocarcinoma
    • "Sarcomatoid salivary gland carcinoma 8033 (/3)": Synonym added:
      • Sarcomatoid salivary duct carcinoma
  • "Squamous cell carcinoma 8070" row:
    • Synonyms added:
      • Epidermoid carcinoma
      • Squamous cell carcinoma
      • Squamous cell epithelioma
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 7: Tumors of Odontogenic and Maxillofacial Bone (Mandible, Maxilla)

  • "Odontogenic carcinosarcoma 9342 (/3)" row:
    • Column 1 histology code changed from 8980 to 9342
    • Subtype/variant removed: "Odontogenic sarcoma/ameloblastic fibrosarcoma 9330/3" (inadvertently appeared twice in the table)
  • "Sarcoma NOS 8800 (/3) row:
    • Synonym added to "Ameloblastic fibrosarcoma 9330 (/3)": "Ameloblastic fibro-odontosarcoma"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 8: Tumors of Ear

  • "Squamous cell carcinoma of the middle ear 8070" row:
    • Synonyms added:
      • Epidermoid carcinoma
      • Squamous cell carcinoma
      • Squamous cell epithelioma
    • Subtype/variant added: "Squamous cell carcinoma, keratinizing type NOS 8071 (/3)"
  • Footnote added to applicable terms: "This term may be used for cases diagnosed 2026 and later."

Table 10: Paired Sites

  • Row deleted: "Nasal cavity (excluding nasal cartilage, nasal septum) (C300)"

Histology Coding Rules

  • H Rules: "Code the subtype/variant when (all tumors are) (there is a) NOS and a single subtype/variant of that NOS such as the following" (changes made to rules in "Single Tumor" and "Multiple Tumors Abstracted as a Single Primary" modules)
    • "(Not exhaustive)" added to main rule statement
    • Bullet removed: "Odontogenic carcinosarcoma 9342 and a subtype/variant of odontogenic carcinosarcoma"
    • Bullet updated: "well differentiated neuroendocrine carcinoma" changed to "neuroendocrine tumor"

Kidney

Table 1: Specific Histologies, NOS, and Subtype/Variants

  • Added Notes 1-3 (to be consistent with other site-groups)
  • "Neuroendocrine tumor 8240 (/3)" row
    • Subtypes added: "Neuroendocrine tumor, grade 2 8249 (/3)"
    • Synonym added: "Neuroendocrine tumor, grade 1"
    • Subtypes removed:
      • "Large cell neuroendocrine carcinoma 8013/3" (moved to NEC row)
      • "Small cell neuroendocrine carcinoma 8041/3" (moved to NEC row)
      • "Extra-adrenal paraganglioma 8693/3" (moved to paraganglioma row)
  • Row added: "Neuroendocrine carcinoma 8246 (/3)"
  • Paraganglioma row: code changed from 9700/3 to 8693
    • Synonym removed: "Extra-adrenal pheochromocytoma"
    • Synonyms added:
      • "Extra-adrenal paraganglioma"
      • "Parasympathetic paraganglioma"
      • "Sympathetic paraganglioma"
  • Sarcoma 8800/3 row: "Peripheral neuroectodermal tumor 9364 (/3)"
    • Synonyms added:
      • "pPNET"
      • "Neuroectodermal tumor NOS"

Lung

Introduction

  • Note 4 regarding obsolete term removed

Terms that are NOT Equivalent or Equal

  • Bullet related to "carcinoma 8010" and "adenocarcinoma 8140" removed

Table 2: Combination/Mixed Histology Codes

  • "Adenosquamous 8560" row: "basaloid" added to footnote
  • "Combined large cell neuroendocrine carcinoma 8013" row: Bullets in column 1 updated

Table 3: Specific Histologies, NOS, and Subtype/Variants

  • Important Note 2 was removed
  • "Adenocarcinoma" row:
    • Adenocarcinoma synonyms simplified
    • "Mucinous adenocarcinoma, minimally invasive 8257 (/3)" removed as a subtype of Mucinous 8253 and added as its own entry
    • "Mucinous adenocarcinoma, microinvasive (/3)" removed from table; footnote added stating the term is not preferred
    • "Non-mucinous adenocarcinoma, microinvasive (/3)" removed from table; footnote added stating the term is not preferred
    • Entries for 8250 combined into one entry

Histology Rules

Coding Histology

  • Instruction #4: Exceptions added for "Pattern"

Histology Coding Rules

  • H Rule: Code the histology when only one histology is present.
    • Added Note 5 regarding when to code pattern.

Malignant CNS

Terms THAT ARE NOT Equivalent or Equal

  • Replaced "carcinoma" for "malignancy" in first bullet note.

Reportability Criteria

  • Instruction #1A-C deleted

Behavior Code

  • Moved up to after Reportability Criteria and no longer labeled as a section; subsequent section headers renumbered
  • Text updated for #1B
  • Added "See A and B above" to #2 and #3
  • Instruction #6 updated to reference the CNS CAP Protocol and sentence added at the end of Instruction #6: "See WHO Grades for Select CNS Neoplasms."
  • Two examples added to the end of section

WHO Grades for Select CNS Neoplasms

  • Note 3 updated to: "WHO does not provide Grades for all CNS and peripheral nerve neoplasms."
  • Note 4 with examples added.
  • WHO Grade Definitions table updated.
  • Deleted Table 1: WHO grade for select CNS neoplasms.
  • Instruction added: "Refer to the most current version of the CNS CAP Protocol for WHO grading of some of the more common CNS tumors."

Directory of Sections and Tables

  • Deleted "Section 1: Behavior Code" from this part and remaining sections renumbered.
  • Subsequent tables renumbered

Table 2: Specific Histologies, NOS, and Subtypes/Variants

  • "Astrocytoma NOS 9400" row: Footnote added
  • "Medulloblastoma NOS 9470" row: 9471 synonyms updated
    • Synonym deleted: "Nodular"
    • Synonym updated: "Desmoplastic" to "Desmoplastic nodular"
  • "Pituitary adenoma/pituitary neuroendocrine tumor 8272 (/3)" row:
    • "Pituitary adenoma/PitNET" added as a synonym
    • Footnote added
  • "Sarcoma NOS 8800" row: Chondrosarcoma 9220: footnote added

Melanoma

Table 2: Specific Histologies, NOS, and Subtype/Variants

  • Behavior codes removed from many histologies which can be either /2 or /3

Table 3: Non-Reportable Terms and Codes

  • Changed the name of the table from Non-Reportable Neoplasms

Multiple Primary Rules

  • M Rule: "Abstract multiple primaries when melanomas are diagnosed more than 60 days apart."
    • Example 3 added

Non-Malignant CNS

"Reportability Criteria for Non-Malignant CNS Neoplasms" section

  • Instruction #1A-C deleted

"Behavior Code" section

  • Moved up to after Reportability Criteria and no longer labeled as a section; subsequent section headers renumbered
  • Deleted 1C and text updated for 1B
  • Added "See A and B above" to #2 and #3
  • Instruction #6 updated to reference the CNS CAP Protocol and sentence added at the end of Instruction #6: "See WHO Grades for Select CNS Neoplasms."
  • Two examples added to the end of section

WHO Grades for Select CNS Neoplasms

  • Note 3 updated to: "WHO does not provide Grades for all CNS and peripheral nerve neoplasms."
  • Note 4 with examples added.
  • WHO Grade Definitions table updated.
  • Deleted Table 1: WHO grade for select CNS neoplasms.
  • Instruction added: "Refer to the most current version of the CNS CAP Protocol for WHO grading of some of the more common CNS tumors."

Directory of Sections and Tables

  • Deleted "Section 1: Behavior Code" from this part and remaining sections renumbered
  • Subsequent tables renumbered

Table 5: Specific Histologies, NOS, and Subtypes/Variants

  • "Pituitary adenoma NOS 8272 (/0)" row: "NOS" added to histology term
    • Footnote added
  • "Solitary fibrous tumor Grade 1 8815 (/1)" row
    • Footnote added

Multiple Primary Rules

  • M Rule: "Abstract multiple primaries when multiple tumors are present in any of the following sites"
    • Meninges of cranial nerves site code corrected to "C700"

Coding Histology

  • Examples removed from item 3B under Ambiguous Terminology and statement added: "See the Ambiguous Terminology section of the General Instructions for instructions and examples on when ambiguous terms and definitive terms may be used to assign histology."
  • List of ambiguous terms deleted.
  • Table 9: List of Ambiguous Terminology added
  • Notes added below Table 9 with information about terms that were previously considered ambiguous terms but are now considered definitive terms.
  • Table 10: List of Definitive Terminology added
  • Tables numbers updated as table 1 deleted.

Other Sites

Site or Site-Group Histology-Specific Tables section

  • Notes 1-3 added

Table 2: Mixed and Combination Codes

  • "Adenocarcinoma with mixed subtypes 8255" row: Footnote added
  • "Liposarcoma NOS 8850" row: Column 2 changed from "Mixed liposarcoma 8855" to "Liposarcoma NOS 8850"
  • Row deleted: "Teratocarcinoma 9081"

Table 3: Prostate Histologies

  • Coding Notes for Ductal adenocarcinoma 8500/3: wording clarified
  • "Acinar adenocarcinoma 8140" row:
    • Synonym added: "Pleomorphic giant cell acinar carcinoma (/3)"
  • "Adenocarcinoma with neuroendocrine differentiation 8574 (/3)"
    • Footnote updated
  • Rows added:
    • "Mixed neuroendocrine–non-neuroendocrine neoplasm 8154 (/3)"
    • "Neuroendocrine carcinoma 8246 (/3)"
      • Including subtypes/variants previously located in the 8240 row; and newly added subtype/variant "Combined small cell neuroendocrine carcinoma 8045 (/3)"
  • "Neuroendocrine tumor 8240 (/3)" row
    • Synonyms removed:
      • "Well differentiated neuroendocrine tumor"
      • "WD neuroendocrine tumor"
    • Synonym added: "Neuroendocrine tumor, grade 1"
    • Subtypes/variants removed (moved to 8246 row):
      • "Large cell neuroendocrine carcinoma 8013 (/3)"
      • "Small cell neuroendocrine carcinoma 8041 (/3)"
    • Subtype/variant added: "Neuroendocrine tumor, grade 2 8249 (/3)"
  • "Squamous cell carcinoma 8070" row: Footnote updated

Table 5: Esophagus Histologies

  • Row added: "Neuroendocrine carcinoma 8246 (/3)"
    • Including subtypes/variants previously located in the 8240 row
  • "Neuroendocrine tumor 8240 (/3)" row
    • Synonym added: "Neuroendocrine tumor, grade 1"
    • Subtypes/variants removed (moved to 8246 row):
      • "Neuroendocrine carcinoma 8246/3"
      • "Large cell neuroendocrine carcinoma 8013 (/3)"
      • "Small cell neuroendocrine carcinoma 8041 (/3)"
    • Subtype/variant added: "Neuroendocrine tumor, grade 2 8249 (/3)" along with synonym "Neuroendocrine tumor, grade 3"

Table 6: Stomach Histologies

  • Coding Notes for Stomach: Bullet 2 added

Table 9: Liver and Intrahepatic Bile Duct Histologies

  • Row added along with footnote: "Mixed neuroendocrine-non-neuroendocrine neoplasm 8154 (/3)"

Table 10: Gallbladder and Extrahepatic Bile Duct Histologies

  • "Bile duct carcinoma 8160" row: Synonym added for "Perihilar cholangiocarcinoma 8162": "Klatskin tumor"

Table 11: Pancreas Histologies

  • "Neuroendocrine tumor NOS 8240" row:
    • Synonym added: "Islet cell tumor"
    • "ACTH-producing neuroendocrine tumor 8158":
      • "neuroendocrine" added to term
      • Synonyms added:
        • "Ectopic ACTH-producing pancreatic neuroendocrine tumor"
        • "ACTH-producing tumor" (moved from main term to synonym)
    • "Serotonin-producing neuroendocrine tumor 8241" row:
      • "neuroendocrine" added to term
      • Synonym added: "Serotonin-producing tumor" (moved from main term to synonym)

Table 12: Thyroid Histologies

  • Thyroid Coding Notes: Bullet 2 added
  • Row added along with footnote: "Invasive encapsulated follicular variant of papillary thyroid carcinoma 8340 (/3)"
  • "Papillary thyroid carcinoma NOS 8260" row: Footnote added to "Follicular variant of papillary thyroid carcinoma 8340"

Table 13: Ovary Histologies

  • "Serous carcinoma NOS 8441" row:
    • Synonyms removed:
      • "Serous tubal intraepithelial carcinoma"
      • "Serous endometrial intraepithelial carcinoma"
    • "Low-grade serous carcinoma 8460 (/3)": Synonym removed:
      • "micropapillary serous carcinoma"

Table 14: Peritoneum Histologies

  • "C481 Specified parts of peritoneum" and "C488 Overlapping lesion of retroperitoneum and peritoneum" added to table

Table 16: Uterine Corpus Histologies

  • Rows added:
    • "Mixed neuroendocrine non-neuroendocrine carcinoma 8154 (/3)" (moved from 8246 row)
    • "Neuroendocrine tumor NOS 8240 (/3)[SA1]"
  • "Neuroendocrine carcinoma NOS 8246 (/3)" row: Subtype/variant removed:
    • "Mixed neuroendocrine non-neuroendocrine carcinoma (MiNEN) 8154" (moved to its own row)
  • "Serous carcinoma NOS 8441" row:
    • Synonyms added:
      • "Endometrial intraepithelial carcinoma (/2)"
      • "EIC"
      • "Serous endometrial intraepithelial carcinoma (/2)" along with footnote
      • "SEIC"

Table 17: Uterine Cervix Histologies

  • Row added: "Mixed neuroendocrine non-neuroendocrine carcinoma 8154 (/3)" (moved from 8246 row)

Table 19: Vulva Histologies

  • Row removed: "Adenoid cystic carcinoma 8200" (inadvertently duplicated in the table)
  • "Sweat gland adenocarcinoma 8400" row: Footnote added to "Adenoid cystic carcinoma 8200"

Table 23: Penis and Scrotum Histologies

  • Penis coding notes: Example 2 added

Multiple Primary Rules

  • M Rule: "Abstract multiple primaries when the patient has a subsequent tumor after being clinically disease-free for…"
    • Exception added
  • M Rule: "Abstract a single primary when synchronous, separate/non-contiguous tumors are on the same row…"
    • Note 2 added

Histology Coding Rules

  • H Rule: "Code the histology when only one histologic type is identified."
    • Note 3 added
  • H Rule: "Code 8077/2 (squamous intraepithelial neoplasia, high grade) for the following..." (changed in both "Single Tumor" and "Multiple Tumors Abstracted as a Single Primary" modules)
    • Bullet added: "High-grade squamous dysplasia"
    • Note 2 updated
  • H Rule: "Code 8148/2 (glandular intraepithelial neoplasia, grade III) for the following..." (changed in both "Single Tumor" and "Multiple Tumors Abstracted as a Single Primary" modules)
    • Bullet added: "High-grade glandular dysplasia"
    • Note updated
  • H Rule: "Code 8140 (adenocarcinoma NOS) for prostate primaries when the diagnosis is..." (changed in both "Single Tumor" and "Multiple Tumors Abstracted as a Single Primary" modules)
    • Bullet added: "Ductal adenocarcinoma when the percentage of duct is not stated or less than 50 percent of the tumor"
    • Note added

Urinary

Table 2: Specific Histologies, NOS, and Subtype/Variants

  • Added Notes 1-3 (to be consistent with other site-groups)
  • Urothelial carcinoma row: 8120: added "urothelial" to the term "poorly differentiated urothelial carcinoma"
  • NET row: Synonyms removed:
    • Well-differentiated neuroendocrine carcinoma
    • Neuroendocrine carcinoma, low grade

Multiple Primary Rules

  • M Rule clarified: "Abstract a single primary when the patient has multiple invasive urothelial cell carcinomas in the bladder."
    • Wording updated for clarity only
  • M rule clarified: "Abstract a single primary when there are urothelial carcinomas in multiple urinary organs."
    • Bullets added to clarify histology and note 1 updated
    • Note 2 added to clarify timing.

    Histology Coding Rules

    • H Rules: "Code the subtype/variant when there is a NOS and a single subtype/variant of that NOS such as the following "–
      • Deleted "Papillary urothelial carcinoma 8130 and a subtype/variant of papillary urothelial carcinoma" listing from single tumor and multiple tumors abstracted as a single primary modules
    • H Rule: "Code mixed small cell carcinoma 8045 when"… grammatical errors corrected (no change in rule)