[Medullary carcinoma of the breast. What remains of this entity today?].

Identified half a century ago as a favorable prognostic form, medullary breast cancer was classified by Ridolfi in 1977 as necessarily combining 5 features: seemingly wall-circumscribed histological limits, a syncytial architecture in at least 75% of the areas examined, inflammation of the stroma containing diffuse lymphocytes and plasma cells, moderate or marked anisonucleosis and absence of tubular differentiation and/or an intraductal component. Defined is this way, it only accounts for one third of breast cancers with stromal invasion and its outcome is significantly more favorable. Although the reproducibility of this classification is not perfect, only the combination of morphological features prevail over the "new" biological characteristics.