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SEER Inquiry System - Report
Produced: 09/10/2025 12:39 AM
Question 20200081
Inquiry Details
References:
Solid Tumor Rules. Other Sites; For use with cases 2007-2021
Question:
Solid Tumor Rules (2018)/Histology--Pancreas: How is the histology coded, and what H Rule applies, for a 2021 diagnosis when the pathological diagnosis is neuroendocrine tumor (NET) G1 or NET G2, but clinically, the tumor is stated to be insulinoma? See Discussion.
Discussion:
Insulinoma, NOS is reportable for cases diagnosed 2021 and later. However, the diagnosis of insulinoma is most frequently made with clinical correlation of the patient's clinical syndrome and serum hormone levels. Despite a pathological diagnosis of NET, this will clinically be stated as insulinoma based on the functional type of tumor. At the largest facility in our area, all pathology reports with a diagnosis of insulinoma over the last year only provide a pathological Final Diagnosis of NET (either G1 or G2), but elsewhere specify, Functional Type: Pancreatic neuroendocrine tumor, functional. Correlation with Clinical Syndrome and Elevated Serum Levels of Hormone Product: Insulin-producing (Insulinoma).
For 2021 and later, it seems this should be accessioned as insulinoma (8151/3), but one cannot arrive at that histology using the current Other Sites (MP/H) H Rules. Following the existing rules, one would code the histology to NET, G1 or NET, G2 (8240 or 8249) per Rule H6. There are technically two specific histologies to consider: NET (either 8240 or 8249) and insulinoma, NOS (8151). Following the H Rules, Rule H6 instructs one to code the histology with the numerically higher ICD-O-3 code (8240 or 8249).
Coding this histology to NET (8240 or 8249) does not seem to reflect the most accurate classification of this tumor, but applying the current rules, this is the only histology that can be coded. There is no current guideline in the Other Sites schema or the ICD-O-3.2 Implementation Guidelines instructing us to ignore the pathological diagnosis of a NET for these tumors (even though insulinomas are NETs). The only SINQ that currently exists (SINQ 20150019) states the histology can be coded as either a NET or an insulinoma in these cases. How are registrars to consistently code histology for these tumors without a rule clarification?
This question was prompted from preparing SEER*Educate coding exercises. We will use the answer as a reference in the rationales.
Answer:
Code the tissue/pathology histology over the clinical diagnosis. Because of implementation timelines, a comprehensive revision to Other Sites rules will not be available 2022. A limited revision is planned and histology tables will be added for select sites. The General Instructions will also be revised for Other Sites.
