Ipsilateral breast metastasis from a pulmonary adenocarcinoma: A case report and a focused review of the literature

Metastases to the breast from extramammary malignancies are extremely rare. Ruling out the diagnosis of primary breast tumor is important in order to decide on clinical management and predict prognosis. We report a case of metastasis to the breast from a pulmonary adenocarcinoma, with extensive micropapillary component, diagnosed concomitantly with the primary tumor. A 52 year-old female patient presented with mammary gland tingling and dyspnea accompanied with fatigued of 4 months duration and a nodular shadows in the front of the upper lobe was found on a chest computed tomography (CT) scan. The original clinical diagnosis was right breast cancer with lung and bone metastasis, or breast and lung double primary cancers. In addition, on physical examination a poorly defined mass was noted in the upper outer quadrant of the right breast. The patient underwent thoracocentesis and breast biopsy. By imageology, cytology, histology and immunohistochemistry, we diagnosed primary lung cancer with metastases to the right breast and bone. The metastatic anatomic sites demonstrated histologically extensive micropapillary component, which is recently recognized as an important prognostic factor. The patient was administered 4 cycles of cisplatin and docetaxel, although no clinical response was seen, the patient is still alive 9 months after diagnosis. The result of immunohistochemistry is a useful supplement in differential diagnosis.