What is *not* a histological feature of invasive breast cancer?

Metastatic calcification is not considered a histological feature of invasive breast cancer. Instead, it is a process that occurs when there is an abnormal deposition of calcium salts in tissues, often associated with conditions like hypercalcemia rather than being a direct reflection of the characteristics of breast cancer itself.

On the other hand, nuclear pleomorphism, vascular invasion, and coarse chromatin are all recognized histological features that can be observed in invasive breast cancer. Nuclear pleomorphism indicates variations in nuclear size and shape, which is a sign of the dysregulated growth and malignancy of cancer cells. Vascular invasion refers to cancer cells infiltrating blood vessels, which is significant as it may lead to metastasis. Coarse chromatin is a feature associated with the atypical nuclei often found in malignant tumors, indicating a high level of genetic activity and potential malignancy. Each of these characteristics contributes to the diagnosis and grading of invasive breast cancer.