Metastasis to Psoas Muscle Detected by F-18FDG PET-CT Imaging

We present the PET-CT images of a 67-year-old man who initially presented with seizures and was found to have a brain metastasis from lung adenocarcinoma. F-18 FDG PET-CT was performed for whole body staging, which showed focal hypermetabolism in the psoas muscle without any definite morphologic changes seen on the coregistered CT. Fused PET-CT images were used for assisting CT-guided needle biopsy, which showed metastatic adenocarcinoma of lung origin. The images show an extremely rare but possible site of metastasis to the psoas muscle detected by F-18 FDG PET before any definite morphologic changes, and CT may help in anatomic localization and biopsy.