Staring secondaries, where is the primary?

An asymptomatic issueless young staff nurse underwent pre-employment health screening and USG abdomen showed multiple hypodense lesions in liver. Further screening with whole body positron emission tomography-computed tomography (PET-CT) scan showed significantly FDG avid mass involving most of the right lobe of liver with multiple large FDG avid lymph nodal metastases. Unsuspected focal abnormal, FDG avid, hyperdense mural nodule was seen in uterus, which is the site of primary.