One year later, in February 2006, a CT scan was performed to further evaluate an elevation in her serum carcinoembryonic antigen levels, which rose to 17.1 ng/mL (normal levels in nonsmokers, < 2.5 ng/mL). Numerous enlarged lymph nodes were present in the right hilum, mediastinum, aortopulmonary window, pretracheal, precarinal, and subcarinal regions (Figs 1
, left, A; right, B; and 2
, top left, A, arrows). A lung mass was not identified, although calcified granulomas were present in the right upper lobe and mediastinum. A poorly marginated low-density mass (5.6 cm in size) was present in the left pelvis. A positron emission tomography (PET) scan using 18F-fluorodeoxyglucose (FDG) was performed based on the CT scan results, and showed increased activity in the right hilum, left hilum, mediastinum, and right paratracheal regions with standardized uptake values (SUVs) of 9.8, 7.0, 9.0, and 7.4 respectively (Fig 2, bottom left, B; right, C [black arrow]; and right, D). Increased activity was also noted in the lower pelvis on the lateral aspect of the rectum, in the iliac lymph nodes, and in the pelvic mass on CT scans, with SUVs of 8.7, 5.0, and 4.7, respectively (Fig 2, right, C [white arrow], and right, D). In a patient with known colon cancer, these findings were most suggestive of metastatic disease, although a second primary in the pelvis and/or the chest was also a consideration.