Neoplasm to neoplasm metastasis. Pheochromocytoma harboring a metastasis of breast cancer.

Breast cancer commonly metastasizes to the adrenal glands. Metastases to an already existing adrenal gland tumor, however, are a rare finding. To our knowledge, this report represents the first case of a breast carcinoma metastasizing to a pheochromocytoma. Metastases of a cancer to another coexisting tumor in the same individual is an unusual event.