#1: Solid Tumor Rules (2018)
#2: Multiple primaries
Source 1: 2018 Solid Tumor Rules
Notes: Breast; July 2019 Update
Solid Tumor Rules (2018)/Multiple primaries--Breast: How many primary tumors should be abstracted for a 2018 breast excision with a final diagnosis of invasive mucinous adenocarcinoma (0.7 cm) with ductal carcinoma in situ (DCIS) present as discontinuous foci, spanning 12 cm? See Discussion.
If the term discontinuous foci means separate tumors, then rule M14 would apply making these multiple reportable tumors.
Abstract two primaries, invasive mucinous and DCIS, using 2018 Solid Tumor Rules for Breast, M14, as the discontinuous foci are separate tumors in this example and the histologies are on different rows of Table 3 of the rules.