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SEER Inquiry System - Report
Produced: 09/18/2025 6:36 PM
Question 20240074
Inquiry Details
References:
#1: Solid Tumor Rules. Head and Neck, 2024 Update
#2: WHO Class H & N Tumors. 5th edition, online version
Question:
Solid Tumor Rules/Histology--Head & Neck: How is histology coded for nasopharyngeal non-keratinizing squamous cell carcinoma, undifferentiated type? See Discussion.
Discussion:
Example: Patient had a 2023 nasopharyngeal mass biopsy showing “Nasopharyngeal non-keratinizing squamous cell carcinoma, undifferentiated type.”
The Head and Neck Solid Tumor Rules (STRs) do not include an H Rule that instructs us how to code histology when there are two subtypes/variants present for a head and neck primary, nor does the STR define undifferentiated carcinoma as a subtype/variant for 8072.
The WHO Classification of Head and Neck Tumors states non-keratinizing nasopharyngeal carcinoma (non-keratinizing squamous cell carcinoma (SCC) is the most common subtype for nasopharyngeal ca, but that non-keratinizing can be subdivided into undifferentiated and differentiated subtypes.
Should histology be 8020 (undifferentiated carcinoma) or 8072 (non-keratinizing SCC)?
Answer:
Assign histology as 8072 for non-keratinizing SCC, undifferentiated subtype.
WHO Classification of Head and Neck Tumors, 5th edition assigns 8072/3 to squamous cell carcinoma, non-keratinizing, NOS in the nasopharynx. As the tumor exhibits a variety of architectural patterns and appearances histologically, they can be further classified as undifferentiated or differentiated subtypes. These subtypes do not change the histology code.
