Three Cases of Atypical Breast Metastasis from Lung Adenocarcinoma.

Metastatic disease to the breast is rare. Melanoma and lymphoma are the most common primary tumors metastasizing to the breast, and breast metastasis from a primary lung neoplasm is uncommon. It can be difficult to distinguish metastatic disease from primary breast cancer clinically. Immunohistochemistry, combined with further diagnostic imaging, play important roles in identifying the primary origin of the malignancy. An accurate diagnosis is imperative for therapeutic planning, and further workup should be considered for unusual cytological patterns. In this report, three cases of pulmonary metastasis to the breast with atypical clinical presentations are presented and discussed.