Metastases to breast from primary lung cancer

Abstract Background Metastatic involvement of the breast is relatively rare and has an incidence of 0.5–3%. Lesions that metastasize to the breast may produce changes that look similar to those of primary breast cancer on mammography, but they are more likely to be multiple and are frequently bilateral. Case presentation A 38-year-old female complaining of progressive proptosis with bilateral palpable breast lumps. She was referred to the breast imaging unit to evaluate the nature of those breast lesions, diagnostic mammography, and complementary ultrasound was done that revealed multiple variable-sized well-defined masses scattered all over their parenchyma. True cut biopsy was taken from one of them that show metastatic carcinoma of non-mammary origin. Immunophenotyping revealed neuroendocrine carcinoma of lung origin. A metastatic workup was done that revealed horrible metastatic deposits in multiple organs and the primary was found in the lung. Conclusions Metastasis to the breast from extra-mammary carcinomas is extremely rare. The most common types are malignant melanoma, secondary lymphomas, and tumors of neuroendocrine origin like Small cell carcinoma. Histopathology and sometimes immunophenotyping can provide the diagnosis.