EP-674 Metastases to the breast from a primary lung adenocarcinoma: A case report and literature review

Abstract

Abstract Background Primary breast cancer is the commonest malignancy in adult females. However, metastases to the breast is a rare occurrence with a frequency of approximately 0.2% - 1.3%. Lung adenocarcinoma is the most common type of lung cancer and distant metastases to other organs carry a poor prognosis. A wide variety of malignancies can metastasise to the breast, melanoma being most common. On review of the literature there is a paucity of published cases of primary lung adenocarcinoma metastasizing to the breast. Case A 77-year-old lady present to the emergency department (ED) with a 5-day history of presyncope. There were no other associated symptoms and the no findings on clinical exam. Computed tomography (CT) of the thorax, abdomen & pelvis reported diffuse opacities in both lungs and a solitary, 3×2cm mass in the upper inner quadrant of the left breast. A core biopsy of the lesion was carried out. Immunohistochemistry did not support a diagnosis of breast carcinoma but strongly suggested a primary lung adenocarcinoma. After a multidisciplinary meeting (MDM) discussion the plan was to commence a course of chemotherapy. Conclusion Given its atypical presentation it can be challenging to distinguish between a primary breast cancer and metastases. Metastatic disease, although rare, should be considered in the differential diagnosis as the treatment and prognosis differ greatly from primary breast cancer. Immunohistochemistry is essential for identifying the primary origin of the tumour.