Tumor-to-tumor metastasis: a rare case of breast carcinoma metastasizing to a pheochromocytoma, and a literature review

Background Tumor-to-tumor metastasis is a well-recognized but uncommon entity. Breast carcinoma is one of the most common metastatic donors. Breast carcinoma metastasizes commonly to adrenal glands. However, the co-existence of a metastatic lesion with an existing adrenal tumor is a rare finding.