Abstract
While metastatic disease to the breast has been documented from many primary neoplasms with incidence ranging from 0.2% to approximately 2.7% among reported clinical cases, breast cancer metastases resulting from a primary lung neoplasm is significantly less commonly reported in the literature. Routes of metastatic spread of lung neoplasms include both hematologic and lymphatic routes. We present a case of biopsy proven lymphangitic spread of primary lung neoplasm to the ipsilateral breast and axillary nodes mimicking inflammatory breast cancer. It remains crucial to differentiate between extramammary diseases with metastatic deposits in the breast from a primary breast neoplasm as treatment remains very different between these entities. As in this case, the pathologic, histologic, and immunohistochemistry analyses are critical in determining the origin of the malignant cells and formulating a treatment plan.