#1: Solid Tumor Rules (2018)
Source 1: 2018 Solid Tumor Rules
Notes: Lung, July 2019 update
Source 2: WHO Class Lung Tumors
Notes: 4th edition
Solid Tumor Rules/Histology--Lung: What is the histology code and what H Rule applies for a diagnosis of well differentiated adenocarcinoma in situ (bronchioloalveolar carcinoma)? See Discussion.
There is no statement of mucinous or non-mucinous in this case, only adenocarcinoma in situ and an obsolete term bronchioloalveolar carcinoma (BAC) which used to be code 8250. However 8250 is now lepidic adenocarcinoma, and does not match this diagnosis.
Although the Histology Rules do include a general note indicating that the preferred term for BAC is now mucinous adenocarcinoma 8253, it is not listed as a synonym in Table 3. As a result it is unclear how to apply this statement in accordance with the H rules.
The ICD-O Histology Updates table also includes Bronchiolo-alveolar carcinoma, non-mucinous which seems to suggest that in order to apply histology code 8252 (non-mucinous) or 8253 (mucinous) one must also have a statement of mucinous or non-mucinous.
Code adenocarcinoma in situ as 8140/2 using the 2018 Lung Solid Tumor Rules, Rule H4 as this single histology is listed as a synonym for adenocarcinoma (8140) in Table 3 . Bronchiolalveolar carcinoma, a synonym for adenocarcinoma in situ, is an obsolete term according to WHO Classification of Tumors of the Lung, Pleura, Thymus and Heart, 4th edition; however, some pathologists add in the no longer preferred term to the diagnosis. When stated as non-mucinous adenocarcinoma in situ, code as 8250/2 for lung only (Rule H2) and mucinous adenocarcinoma in situ as 8253/2 (Rule H1).
Note: WHO published a corrected 4th Ed Lung blue book fixing the 8410 error.