Primary synchronous malignancies of the breast and the kidney

Synchronous primary malignancies are most frequently seen with cancers of the stomach and oesophagus, mainly attributed to the similar genetic mutations. Most of these multiple malignancies turn out to be metastatic or metachronous lesions. Multiple synchronous malignancies are rarer than metachronous ones. Primary synchronous breast and renal cancer is even rare. These patients require extensive workup to exclude all possible metastases. The nature of the primary tumours must also be confirmed, prior to any treatment strategy. We report the case of a healthy, middle-aged woman who initially presented with a lesion suspicious for breast carcinoma, and further workup revealed the presence of an asymptomatic, synchronous primary renal cell cancer, which is a very rare presentation.