What diagnostic feature is typical of metastatic breast cancer in lung tissue?

In the context of metastatic breast cancer in lung tissue, the diagnostic feature that is typically observed is the presence of pleomorphic cells with or without tubule formation. This is characteristic of invasive breast carcinoma, which often metastasizes to the lungs.

Pleomorphic cells refer to cells that vary in shape and size, indicating a degree of cellular atypia common in malignant tumors. This variability is a hallmark of aggressive cancers, including breast cancer. Additionally, the formation of tubules may occur in certain types of breast cancer, reflecting the glandular differentiation of the tumor cells, which can help pathologists identify the origin of the metastatic cells.

In contrast, other features mentioned in the choices do not align with what is typically seen in metastatic breast cancer. Necrosis and calcification are more broadly associated with various types of cancers and not specifically indicative of breast cancer metastasis to the lung. The presence of squamous cells with keratinization suggests squamous cell carcinoma rather than breast cancer, and giant cells are often associated with granulomatous inflammation or certain types of primary malignancies like sarcomas, rather than being a feature of breast cancer spread. Thus, the key diagnostic feature of metastatic breast cancer in lung tissue is the presence of pleomorphic cells with