Inflammatory breast cancer: The pathologists' perspective

Inflammatory breast cancer (IBC) is a clinico-pathological entity, which has specific features of inflammation and pathological evidence of cancer, most often involving dermal lymphatics. This review looks at IBC from the pathologists point of view. The diagnostic criteria and differential diagnosis are summarized first. The staging implications are described next. Despite the overall poor prognosis of IBC, it is heterogeneous in terms of most prognostic and predictive factors (such as histological type, grade, receptor status, intrinsic subtype, inflammatory infiltrate). It seems that some molecular features (genes expressed) are unique to IBC, and this may help to identify them as IBC at the molecular level. The key carcinogenetic pathways activated in IBC, the inflammatory pathways present in the disease as well as the relation of IBC to cancer stem cells are also briefly covered. Due to the relative rarity of IBC, preclinical trials are very important in the study of this entity, and models with stromal and microenvironmental elements are expected to outperform the traditional models without these features, as the microenvironment seems to be a key component of IBC.