Solid Tumor Rules (2018)/Multiple Primaries--Breast: The December 2020 revision to 2018 Breast Solid Tumor Rules, Rule M10, using behavior rather than timing to determine the number of primaries, has caused synchronous separate/non-contiguous tumors reported as invasive carcinoma, NST (8500/3) and lobular carcinoma in situ (8520/2) (or vice versa) to be reported as separate primaries per Rule M14. Should an invasive carcinoma NST and a synchronous, separate lobular carcinoma in situ be separate primaries per M14? See Discussion.
Solid Tumor Rules (2018)/Multiple Primaries--Breast: Is a breast resection showing invasive mucinous carcinoma in a single tumor with associated ductal carcinoma in situ and additional findings of a background of lobular carcinoma in situ single or multiple primaries and which M rule applies? See Discussion
Solid Tumor Rules (2018)/Multiple Primaries--Breast: How many primaries are accessioned when there are multiple synchronous/non-contiguous tumors when one tumor is metaplastic carcinoma (with carcinoma No Special Type (NST) or lobular carcinoma) and another tumor is strictly carcinoma, NST? See Discussion.
Solid Tumor Rules (2018)/Multiple Primaries--Brain: How many primaries are there and what M Rule applies when two tumors identified in the brain are pathologically proven to be glioblastoma, IDH-wild type and anaplastic astrocytoma per the pathology report final diagnosis, but the diagnosis comment and tumor board indicates multifocal glioblastoma is favored? See Discussion.
Solid Tumor Rules (2018)/Laterality--Brain and CNS: How is laterality coded for bilateral non-malignant central nervous system (CNS) or malignant CNS tumors now that laterality is no longer used to identify these tumors as multiple primaries? See Discussion.
Solid Tumor Rules (2018)/Histology--Thyroid: What is the correct histology code for a micropapillary thyroid carcinoma for cases diagnosed 1/1/2021 and later? See Discussion.
Solid Tumor Rules (2018)/Histology--Prostate: How is the histology coded for a diagnosis of mixed prostatic adenocarcinoma (5%) and small cell neuroendocrine carcinoma (95%) from a transurethral resection of the prostate? See Discussion.
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.