Breast MR imaging in a patient with unilateral axillary lymphadenopathy and unknown primary malignancy.

Bilateral invasive breast cancers were detected on MR imaging in a patient with left unilateral axillary lymphadenopathy and normal findings at physical examination, mammography, and ultrasound of both breasts. One spiculated and a second ill-defined enhancing lesion in the left breast as well as a superficial circumscribed lesion in the right breast were proven to be invasive malignancies. In patients with isolated axillary lymph nodes and occult primary malignancy, breast MRI can identify or exclude the breast as primary site, which proves the superiority and diagnostic benefit of this imaging method and also its contribution to the therapeutic approach.