Breast MRI of occult primary breast cancer

Breast MRI can be useful for identifying an occult primary breast cancer when a patient presents with an unknown primary cancer. This MRI depicts a patient who presented with an axillary lymph node metastasis with an unremarkable clinical breast examination and a negative mammogram. The MRI detected a 6 mm suspiciously enhancing irregular mass in the outer inferior right breast (arrow). Biopsy revealed an invasive lobular carcinoma.