Invasive ductal breast carcinoma

The most common type of invasive breast carcinoma, accounting for approximately 70% of breast carcinomas. The gross appearance is usually typical with an irregular stellate outline. Microscopically, randomly arranged epithelial elements are seen. When large sheets of malignant cells are present, necrosis may be seen. With adequate tissue sampling, in situ carcinoma can be demonstrated in association with the infiltrating carcinoma. The in situ component is nearly always ductal but occasionally may be lobular or both.