Are You a Pseudotumor?

Distinguishing a benign inflammatory pseudotumor from a malignant lesion is not easy. Preliminary study results suggest that gadoxetate disodium (Primovist®) might do the job.

Inflammatory pseudotumors (IPT) are rare and they are benign lesions that have been detected in various organs. In diagnostics, these tumors represent a specific challenge, as they can well mimic a malignant lesion. Shintaro Ichikawa, University of Yamanashi, Japan, investigated whether gadoxetate disodium (Primovist®)-enhanced MRI could differentiate between a pseudotumor and a colorectal liver metastasis (CLM).

Method

Ichikawa focused on two key imaging features: a central hypointense area and a peripheral hyperintense rim on the hepatobiliary phase (HBP). Ichikawa measured the lesion-to-liver signal intensity (SI) ratio (LLR) on the HBP and on diffusion-weighted imaging (DWI) in two IPT and three CLM cases.

Results

Ichikawa found a significant difference (p=0.0011) for ratios on HBP and DWI. The IPT had a higher lesion-to-liver ratio on the HBP and a lower LLR on DWI than the CLM.

Conclusion and Discussion

Ichikawa concluded that gadoxetate disodium provides reliable imaging features for distinguishing IPT from CLM. The chair of the session, Marc Zins, Hôpital Paris Saint Joseph, France, asked whether Ichikawa thought that his measurements were reliable enough to avoid biopsy in the patient. Ichikawa answered that he thought biopsy was still useful.