Contralateral axillary involvement in breast cancer recurrence: locoregional disease or metastasis?

We describe a case of right mammary homolateral recurrence with controlateral axillary invasion. The absence of occult involvement of the left breast was confirmed by MRI. A subsequent thoraco-abdomino-pelvic scan and bone scintigraphy did not reveal any metastases. Lymphoscintigraphy of the right breast, after periareolar injection, revealed lymphatic drainage from the right breast into the left contralateral axillary lymph node. Because of the changes in axillary drainage after mammary and axillary surgery observed by lymphoscintigraphy, contralateral axillary involvement could be considered as locoregional disease in the same way as homolateral lymph node involvement.