Invasive breast cancer in the context of Invasive ductal carcinoma

Invasive carcinoma of no special type (invasive carcinoma NST), invasive breast carcinoma of no special type (IBC-NST), invasive ductal carcinoma (IDC), infiltrating ductal carcinoma (IDC) or invasive ductal carcinoma, not otherwise specified (NOS) is a disease. For international audiences this article will use "invasive carcinoma NST" because it is the preferred term of the World Health Organization (WHO).

Invasive carcinoma NST accounts for half of all breast cancer diagnoses in women and is the most common type of invasive breast cancer. It is also the most commonly diagnosed form of male breast cancer. Invasive carcinoma NST is classified by its microscopic, molecular, and genetic features. Microscopically it is a breast carcinoma of the adenocarcinoma type, originating from the breast ducts. It shows invasive features but lacks the "specific differentiating features" of other types of invasive breast cancers. Invasive carcinoma NST is a diagnosis of exclusion, which means that for the diagnosis to be made all the other specific types must be ruled out. There are several rare sub-types of invasive carcinoma NST including pleomorphic carcinoma, carcinoma with osteoclast-like stromal giant cells, carcinoma with choriocarcinomatous features, and carcinoma with melanotic features.