A case of cerebral metastases of unknown origin - Utility of F-18FDG positron emission tomography to localize the primary tumor

Metastatic carcinoma from an unknown primary neoplasm accounts for 3% to 5% of all newly diagnosed malignant lesions, but only 20% to 25% of primary sites are identified. The authors describe a 72-year-old woman with cerebral metastases of unknown origin. After an unsuccessful conventional diagnostic workup, including physical examination, morphologic imaging, and biologic screening, the whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) scan revealed a primary neoplasm in the left breast, which was confirmed by histologic analysis after ultrasonography-guided biopsy.