MRI of the breast in patients with metastatic disease of unknown primary

The objective of this study was to assess the value of contrast-enhanced dynamic breast imaging in patients with carcinoma of unknown primary (CUP). Fourteen patients presenting with metastatic disease compatible with breast cancer (axillary lymph node metastasis: n = 6; supraclavicular lymph node metastasis: n = 1; bone metastasis: n = 3; liver metastasis: n = 3; lung metastasis: n = 1), who had no evidence of tumor in X-ray mammograms and ultrasound, underwent bilateral dynamic breast MR imaging. Suspicious lesions were localized preoperatively using a stereotactic device for MR-guided localization procedures. Magnetic resonance imaging revealed suspicious lesions in 9 of 14 patients. Histopathology revealed invasive carcinoma of the breast in 6 of these patients. Two enhancing lesions were fibroadenomas; one proved to be sclerosing adenosis. In 5 patients MR imaging showed no abnormality. Follow-ups performed up to 1 year after initial treatment revealed no breast cancers in these 5 patients. In patients with metastatic disease of unknown primary, MRI of the breast depicts the primary in a considerable number of cases with normal conventional evaluation. Received: 20 February 1998; Revision received: 2 June 1998; Accepted: 10 July 1998