Intramammary metastasis of renal cell carcinoma (RCC) is extremely rare, accounting for only 1.5% of all intramammary metastases. Distinguishing intramammary metastases from benign tumors and breast cancer is clinically problematic. Some patients undergo excessive surgery after a misdiagnosis of breast cancer instead of a mammary tumor. We performed a core needle biopsy (CNB) of a breast mass that developed in a 71-year-old woman after surgeries for bilateral RCC and breast cancer, leading to a diagnosis of intramammary metastasis of RCC. In this case, the CNB and immunohistochemical examination were critical for reaching a definitive diagnosis. We conclude that, when examining patients with mammary tumors, establishing their history of malignant tumors may help diagnose intramammary metastasis and select the best treatment strategy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.