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Produced: 09/18/2025 5:12 PM
Question 20240007
Inquiry Details
References:
#1: ICD-O-3.2
#2: NAACCR Implementation Guidelines. 2024 Guidelines
Question:
Histology--Brain and CNS: Provide clarification about the priority order of histology coding sources and an explanation of why the annotated histology lists are not the same as the WHO IARC ICD-O-3.2 Excel Table (adopted 1/1/2021). See Discussion.
Discussion:
We have had multiple users unable to find the applicable histology in the ICD-O-3.2 (i.e., the site-specific table did not include the histology) because they were using the annotated histology list and could not find the complete list of related terms or synonyms for the histology code.
For example, the ICD-O-3.2 lists Medulloblastoma, SHH-activated, NOS as a related term for 9471/3, but many users were unable to find this valid histology because they were using the annotated histology list, not the ICD-O-3.2.
Answer:
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).
