#1: Solid Tumor Rules (2018)
Source 1: 2018 Solid Tumor Rules
Notes: Breast; July 2019 Update
Solid Tumor Rules (2018)/Histology--Breast: How should histology be coded for 2020 breast lumpectomy final diagnosis of invasive ductal carcinoma? Summary Cancer Data and CAP Summary states: Invasive carcinoma with the following features: Histologic type: Tubular adenocarcinoma. See Discussion.
Per the 2018 Solid Tumor Rules instructions, Final Diagnosis and Staging Summary (synoptic report) have equal coding priority. However, it is unclear which takes priority, or if this should be a combination of components, when the histologies are two different specific histologic types per Table 3 of the Breast Solid Tumor Rules Manual.
In this case, the pathologist states two different histologies. Per the H rules, when there are different histologies, code the histology which comprises the majority of tumor. Use H16 and code histology stated to be more than 50% of tumor OR H17, code 8523 when percentage is not stated or unknown.