Classification Invasive ductal carcinoma is a heterogeneous group with many different subtypes, some of them extremely rare. Each of these variants is associated with another pathological presentation and with a different prognosis compared to invasive ductal carcinoma of no special type (NST). As shown in Figure 1, some of the most important subclassifications are: Medullary carcinoma: younger...

Most breast malignancies arise from epithelial elements and are categorized as carcinomas. IDC not otherwise specified (NOS) and ductal carcinoma in situ are common breast cancers and account for about 85% of breast cancers (1). Unusual breast malignancies may be broadly divided into ILC, well-differentiated subtypes of IDC, cancers of stromal origin, and metastatic neoplasms (2). Well-differen...

Mammary carcinoma arising in microglandular adenosis (MGA) is extremely rare, and MGA is regarded as a non-obligate precursor of triple-negative breast cancer. We report five cases of carcinoma arising in MGA of the breast. All cases showed a spectrum of proliferative lesions ranging from MGA to atypical MGA, ductal carcinoma in situ or invasive carcinoma. Immunohistochemically, all cases were ...