Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients

18-Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has previ ously been used successfully to image primary and metastatic breast cancer. In this pilot study, 19 breast cancer patients with symptoms/signs referra ble to the brachial plexus were evaluated with (18)FDG-PET. In 11 cases com puterized tomography (CT) scanning was also performed. Of the 19 patients r eferred for PET study, 14 had abnormal uptake of (18)FDG in the region of t he symptomatic plexus. Four patients had normal PET studies and one had inc reased FDG uptake in the chest wall that accounted for her axillary pain. C T scans were performed in 9 of the 14 patients who had positive brachial pl exus PET studies; six of these were either normal or showed no clear eviden ce of recurrent disease, while three CTs demonstrated clear brachial plexus involvement, Of two of the four patients with normal PET studies, one has had complete resolution of symptoms untreated while the other was found to have cervical disc herniation on magnetic resonance imaging (MRI) scan. The remaining two patients almost certainly had radiation-induced plexopathy a nd had normal CT, MRI and PET study. These data suggest that (18)FDG-PET sc anning is a useful tool in evaluation of patients with suspected metastatic plexopathy, particularly if other imaging studies are normal. It may also be useful in distinguishing between radiation-induced and metastatic plexop athy.