Hepatic inflammatory pseudotumor mimicking malignancy: the value of differential diagnosis on contrast enhanced ultrasound

Abstract

The aim of this study is to investigate whether the use of contrast enhanced ultrasound (CEUS) can improve the differential diagnostic performance between hepatic inflammatory pseudotumor (HIPT) and other malignant tumors.Material and methods: Forty-four patients with histological proven HIPTs were included in this retrospective study. The features of conventional ultrasound (US) and CEUS were evaluated.Results: Three kinds of enhanced pattern can be seen in the 44 nodules including homogeneous (n=18, 41%), heterogeneous (n=16, 36%) and rim-like enhancement (n=10, 23%). All of the nodules showed hypo-enhancement during the portal and delayed phase. The dominant nodules (n=29, 66%) presented wash-out within 60 s after contrast injection. Quick wash-in and wash-out was seen in 18 nodules (41%). Eighteen nodules (41%) were correctly diagnosed as HIPT, whereas the remaining 26 cases were misdiagnosed as malignancies (n=20, 45%) or with an uncertain diagnosis (n=6, 14%).Conclusion: CEUS was not enough to differentiate HIPT from hepatic malignancies, especially intrahepatic cholangiocarcinoma and liver metastasis. However, some CEUS imaging characteristics may be helpful for HIPT diagnosis

Distinguishing Hepatocellular Carcinoma From Hepatic Inflammatory Pseudotumor Using a Nomogram Based on Contrast-Enhanced Ultrasound

“…Surprisingly, early washout (<60 s) indicated higher probability of IPT. Previous study showed that around 40% of enhanced IPT had quick wash-in and wash-out (6). In our study, 61.9% of IPT patients have early washout, suggesting an even earlier washout in IPT.…”

“…Hepatic IPT often presents with atypical symptoms such as abdominal pain, fever, and nonspecific lab results, and therefore diagnosis is challenging and largely relies on the pathologic findings (2,3). Moreover, IPT has a potential for mimicking malignant tumors, such as hepatocellular carcinoma (HCC) (4)(5)(6). Around 60% of IPT patients had to receive surgery because a malignancy was suspected even with the imaging results (3).…”

“…However, HCC shares some overlapping ultrasonographic features with IPT (1,3,6). Typical CEUS for HCC is a quick wash-in in the arterial phase followed by a quick wash-out (12).…”

“…On the other hand, IPT as a benign tumor, have no enhancement in CEUS. However, atypical IPT presents with various patterns of enhancement in the arterial phase with hypoenhancement during the portal and delayed phases, and 40% of them had quick wash-in and wash-out, which resembles the CEUS feature of HCC (3,6). Additionally, HCC in two-dimensional ultrasound is hypoechoic, and dark areas of fluid or heterogeneous echo can appear when necrosis or hemorrhage occurs (11).…”

“…To the best of our knowledge, there has been no study that develops a model to distinguish between HCC and IPT. Due to the rareness of IPT, most literatures described IPT in case reports (5,6).…”