Multitumor breast cancer — new pathomorphologic classification of multiple simultaneous ipsilateral primary carcinomas

Abstract

Multiple simultaneous ipsilateral breast cancer incidence is some 10% of new breast cancer cases. Update of clinical-
-pathological view of multitumor breast cancer in the context of 7th Edition of AJCC Classification is the main aim of
this article. 7th Edition of AJCC Classification does not apply terms multifocal and multicentric for multitumor breast
carcinomas. Term multiple carcinoma is used instead for all cases of multiple unilateral breast carcinomas. 7th Edition
of AJCC Classification defines multiple carcinomas as follows: multiple tumors grossly presented in the same breast,
tumors are separated by at least 0.5 cm, invasion is confirmed by microscopic evaluation, microscopically confirmed
absents of invasion in breast tissue between tumors.
7th Edition of AJCC Classification considers mainly the dimension of the largest invasive tumor in cases of multiple
carcinomas. Presence of additional tumors with invasive histology is reported only by parameter “m”(e.g., pT(m)1c) or
by a parameter considering number of tumors (e.g., pT(3)1c — for three invasive breast carcinoma tumors, in which
the largest one is more than 1cm and up to 2 cm in diameter.