medullary breast carcinoma medullary breast carcinoma medullary breast carcinoma is a rare type of breast cancer that is characterized as a relatively circumscribed tumor with pushing, rather than infiltrating, margins. it is histologically characterized as poorly differentiated cells with abundant cytoplasm and pleomorphic high grade vesicular nuclei. it involves lymphocytic (a type of white blood cell) infiltration in and around the tumor and can appear to be brown in appearance with necrosis and hemorrhage. prognosis is measured through staging but can often be treated successfully and has a better prognosis than other infiltrating breast carcinomas. medullary carcinoma of the breastspecialtyoncology, pathology medullary breast carcinoma is one of five types of epithelial breast cancer: ductal, lobular, medullary, colloid, and tubular. very rare cases of it have been diagnosed in men (see male breast cancer). ductal carcinoma in situ (dcis) is less commonly present, and medullary breast cancer presents as a soft, fleshy mass with a pushing border. tumors commonly possess mutations of e-cadherin, which results in its overexpression. strengthened adhesions between tumor cells reduce the frequency of metastasis. epidemiology it tends to occur more often in younger women and is more frequently found in those with brca1 gene mutations. although this breast carcinoma is more frequently found in brca 1 gene mutations, most individuals with brca 1 gene mutations do not have medullary breast carcinoma. medullary breast carcinoma is rare and can be seen in about less than 5% of invasive breast cancers. due to the complicated nature of classification, there are difficulties in subtyping this type of breast cancer. diagnosis