Objectives: To identify adrenal masses showing gradual persistent enhancement on delayed contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI).
Materials and methods: Computed tomography or magnetic resonance images of pathologically proven 400 adrenal tumors were retrospectively reviewed over a 10-year period. We included only adrenal tumors showing gradual persistent enhancement on CT and MRI performed at 15 and 5 min, respectively, after contrast material injection.
Results: Four tumors in four patients (three men and one woman; mean age, 51 years) met the inclusion criteria. These lesions were as follows: two ganglioneuromas, one myelolipoma with infarction, and one angiomyolipoma with minimal fat. All of these tumors showed gradual persistent enhancement, and highest attenuation during delayed contrast-enhanced CT or strongest enhancement during delayed contrast-enhanced MRI.
Conclusion: The differential diagnosis of adrenal tumors showing gradual persistent enhancement on delayed contrast-enhanced CT and MRI should include ganglioneuroma, myelolipoma with infarction, and angiomyolipoma with minimal fat.