Oncologic pitfalls and mimics in the abdomen and pelvis.

Oncological imaging in the abdomen and pelvis can be complex. Several imaging pitfalls and mimics of oncology can create diagnostic uncertainty. A pitfall is a malignancy that is missed, either not visualized or misdiagnosed as a benign finding. A mimic is a benign entity that is misinterpreted as malignancy. This article will provide a case-based review with teaching tips to avoid various oncologic pitfalls and mimics in the abdomen and pelvis. The categories of pitfalls to be reviewed include spontaneous regression of primary malignancy, neoplasms resembling benign entities, eye-catching benign pathology with superimposed malignancy, false negative tumor markers, infiltrative malignancy, nuances with disease progression, and concomitant complications. The categories of mimics to be reviewed include benign neoplasms with aggressive growth pattern, benign entities with malignancy appearing enhancement patterns, infectious/inflammatory conditions, iatrogenic/foreign body reactions, and anatomic structures. Insight regarding certain pitfalls and mimics can help the radiologist improve diagnostic precision.