Malignant internal mammary lymph nodes during mobilization of the internal mammary artery

Malignant internal mammary node involvement may occur with a primary neoplasm or with metastasis. The incidental discovery of malignant internal mammary nodes from an unknown primary origin has not been previously described. Cardiac surgeons should be aware of pathologic internal mammary artery (IMA) nodes and any abnormally enlarged nodes encountered in the course of IMA mobilization should be sent for histological examination. The incidental discovery of malignancy does not preclude the use of the IMA as a bypass conduit. Once a diagnosis of malignancy is established, meticulous exhaustive investigation may be indicated to identify the primary lesion and definitive treatment instituted if appropriate.