Pleomorphic lobular breast carcinoma with osteoclast like giant cells in the era of genomic testing

Abstract Pleomorphic lobular carcinoma (PLC) of the breast with osteoclast like giant cells (OGC) is a very rare variant of lobular carcinoma associated with tumour-associated macrophages (TAM) in the microenvironment. High content of TAM in breast cancer is associated with poor survival rates. Using genomic testing for the individual risk assessment in breast cancers with special features of their microenvironment might be skewed by the fact, that most recommended tests investigate proliferation and oestrogen receptor associated genes of tumour cells in their risk stratification but do not take into consideration the microenvironment. So far, no disease-specific molecular alteration could be identified in NST and lobular invasive carcinoma with OGC.