Metastases of primary mixed no-special type and lobular breast cancer display an exclusive lobular histology

• DOI: 10.1016/j.breast.2024.103732
• Publication Date: 2024-04-12T16:12:28Z
• Authors: Gitte Zels; Karen Van Baelen; Maxim De Schepper; Kristien Borremans; Tatjana Geukens; Edoardo Isnaldi; Hava Izci; Sophia Leduc; Amena Mahdami; Marion Maetens; Ha Linh Nguyen; Anirudh Pabba; François Richard; Josephine Van Cau...; Ann Smeets; Ines Nevelsteen; Patrick Neven; Hans Wildiers; Wouter Van Den Bo...; Giuseppe Floris; Christine Desmedt
• Keywords: 0301 basic medicine; Short Communication; mixed invasive breast cancer of no-special type and invasive lobular cancer; E-cadherin; Neoplasms. Tumors. Oncology. Including cancer and carcinogens; Breast Neoplasms; Middle Aged; Cadherins; Metastatic disease; Carcinoma, Lobular; 03 medical and health sciences; Humans; Female; Autopsy; RC254-282; Aged

Primary tumors with a mixed invasive breast carcinoma of no-special type (IBC-NST) and invasive lobular cancer (ILC) histology are present in approximately five percent of all patients with breast cancer and are understudied at the metastatic level. Here, we characterized the histology of metastases from two patients with primary mixed IBC-NST/ILC from the postmortem tissue donation program UPTIDER (NCT04531696). The 14 and 43 metastatic lesions collected at autopsy had morphological features and E-cadherin staining patterns consistent with pure ILC. While our findings still require further validation, they may challenge current clinical practice and imaging modalities used in these patients.