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SEER Inquiry System - Report
Produced: 01/16/2026 11:27 AM
Question 20160065
Inquiry Details
References:
WHO Class Lung Tumors. 3rd and 4th editions
Question:
MP/H Rules/Histology--Lung: What histology code and MP/H Rule applies to the Histologic Type described as adenocarcinoma, mixed invasive mucinous and non-mucinous which involves multiple lung tumors present in a single lobe? See Discussion.
Discussion:
The patient had a lower lobectomy with final diagnosis of adenocarcinoma with the following features: Tumor Focality: Multiple separate tumor nodules in same lobe; Tumor Size: 2.6 cm, 0.7 cm, 0.3 cm and 0.1 cm in greatest dimension; Histologic Type: Adenocarcinoma, mixed invasive mucinous and non-mucinous adenocarcinoma; Histologic Grade: Moderately differentiated.
Answer:
Assign histology code 8254/3.
The 2007 MP/H Lung rules do not include coding guidelines for mixed mucinous and non-mucinous tumors. Lung Table 1 (in the Terms and Definitions, pages 37-38, http://seer.cancer.gov/tools/mphrules/mphrules_definitions.pdf ) is very specific about which histologies can be coded to mixed adenocarcinoma (8255/3). Mucinous is not included per the note at the end of Table 1. Per WHO 3rd and 4th Ed Tumors of the Lung, mixed mucinous and non-mucinous tumors of the lung are classified as 8254/3. Mixed invasive mucinous and non-mucinous adenocarcinoma is a synonym for BAC, mucinous and non-mucinous.
