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SEER Inquiry System - Report
Produced: 03/20/2026 5:56 PM
Question 20230068
Inquiry Details
References:
#1: WHO Class Endocrine Tumors, 81-91; 100-103. 5th edition
#2: Solid Tumor Rules. Other Sites, May 2023 Update
Question:
Solid Tumor Rules/Histology--Thyroid: What is the histology code for a diagnosis of poorly differentiated thyroid carcinoma arising in a background of solid papillary thyroid carcinoma? See Discussion.
Discussion:
Patient had a hemithyroidectomy with the final diagnosis above. There does not appear to be an Other Sites H rule or table that addresses this combination of histologies for thyroid primaries.
Answer:
Code to poorly differentiated thyroid carcinoma, 8337/3.
In this case the tumor is comrpised of two difffernat thyroid histologies: poorly differentiated carcinoma 8337/3 and papillary thyroid carcinoma 8260/3. WHO does not have a code for this combination. Per our endocrine pathology expert, the poorly differentiated carcinoma is the more agressive histology and will determine treatment and progrnosis.
