#1: Solid Tumor Rules (2018)
Source 1: 2018 Solid Tumor Rules
Notes: Colon, January 2019 Update
Source 2: SINQ 20170058
Solid Tumor Rules (2018)/Histology--Colon: Is the term phenotype equivalent to type, subtype, variant for the purpose of coding histology? See Discussion.
In our region, pathologists often describe histology using the term phenotype. However, the use of the term phenotype is not discussed in the Solid Tumor Manual.
Example: Final Diagnosis of a colon tumor is invasive adenocarcinoma with a mixed phenotype, and the Diagnosis Comment states: The majority of the disease is poorly differentiated/signet ring cell phenotype.
Would the histology be coded to 8490 (signet ring cell carcinoma), if the majority of the tumor is a more specific histology described by the term phenotype?
While variant, type, and subtype can be used interchangeably according to the Solid Tumor Rules, SINQ 20170058 states that the Multiple Primaries/Histology (now Solid Tumor) Rules do not include coding phenotype. Code as invasive adenocarcinoma NOS (8140).