Differentiating primary from metastatic ovarian tumors of gastrointestinal origin by CT

•There is large imaging overlap between primary and metastatic ovarian lesions on CT.•Correlate with tumor markers and cancer history when new ovarian lesion identified.•Look for primary malignancy on CT, particularly appendix, gastric/colon and pancreas.•Metastasis is an important consideration with ovarian lesions seen on CT.•Raising possibility of metastatic ovarian lesions can guide patients to proper care. To determine differentiating CT imaging features of primary ovarian cancers from ovarian metastases of gastrointestinal origin. Retrospective study of 50 patients with new ovarian lesions on CT, half were primary ovarian cancers and half gastrointestinal metastases. Two blinded independent readers described tumor characteristics on CT (size, laterality, margin, etc.) and ancillary features (ascites, peritoneal seeding, lymphadenopathy, etc.). Patient age, sex, cancer history, and tumor marker levels for CA-125 and CEA were collected. Wilcoxon test and Pearson's chi-squared test were used for statistical analysis. 50 patients with mean age of 62.1 years were included. Ovarian metastases were more likely to be cystic/mainly cystic (p=0.013), have smooth margins (p=0.011), and have no/mild enhancement (p