Tumor to Tumor: Metastatic Lobular Breast Carcinoma into Primary Clear Cell Renal Cell Carcinoma

Tumor to tumor condition is a rare phenomenon described in up to 15% of tumor in patients that present more than one primary tumor simultaneously. The most common metastatic donor primary tumor is lung carcinoma, followed by invasive ductal carcinoma of the breast, prostatic acinar adenocarcinoma, and papillary thyroid carcinoma. Herein, we present a case regarding a 61 year-old tumor patient who developed a metastasis of lobular carcinoma of the breast over a primary clear cell renal cell carcinoma diagnosed incidentally.