Hepatic inflammatory pseudotumor: educational value of an incorrect diagnosis at contrast-enhanced ultrasound

Washout on Contrast-Enhanced Ultrasound of Benign Focal Liver Lesions-A Review on Its Frequency and Possible Causes

In all imaging methods, including contrast-enhanced ultrasound (CEUS), enhancement in the late phase (LP) is an important criterion for differentiating between benign and malignant focal liver lesions (FLLs). In general, malignant liver lesions are characterized by hypoenhancement and washout in the LP. A lesion with LP hyperenhancement or isoenhancement in the non-cirrhotic liver is usually benign. However, LP hypoenhancement in benign lesions is not so rare, and is even normal and the standard for some lesions, and there are exceptions for each tumor entity that can represent a diagnostic challenge. Knowing these contrast patterns and exceptions is key for correct diagnosis and patient management. The following narrative review describes the contrast behaviors and the frequency of washout and LP hypoenhancement for common as well as rare benign liver lesions and analyzes its causes.

The role of CEUS in diagnosing tuberculous abscess of the right diaphragm

PURPOSE

To evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in detecting tuberculous diaphragmatic abscess (TDA) of the right diaphragm and provide a reference for its clinical diagnosis.

METHODS

A retrospective analysis was conducted on 33 patients with right TDA confirmed via surgery and biopsy. The diagnostic accuracy of CEUS and routine ultrasound for detecting right TDA was compared.

RESULTS

Among the 33 right TDA cases, the lesions primarily exhibited mixed and low echogenicity, with an orientation parallel to the diaphragmatic surface. Eighteen patients (54.5%) demonstrated the characteristic "crocodile mouth sign." Heterogeneous enhancement was observed in most cases (24 patients) compared to homogeneous or no enhancement. The diagnostic accuracy of routine ultrasound for right TDA was 54.50% (18/33), whereas CEUS demonstrated a significantly higher accuracy of 78.78% (26/33) (χ2 = 4.364, P = 0.037).

CONCLUSION

CEUS provides valuable insights into the vascular characteristics of right TDA, with most cases showing mixed echogenicity and heterogeneous enhancement. The "crocodile mouth sign" was a distinctive feature, highlighting the utility of CEUS in improving diagnostic accuracy for right TDA.

Chemotherapy-Induced Liver Injury in Patients with Colorectal Liver Metastases: Findings from MR Imaging

Chemotherapy-induced liver injury has been found to be quite common in cancer patients undergoing chemotherapy. Being aware of chemotherapy-induced hepatotoxicity is important for avoiding errors in detecting liver metastases and for defining the most appropriate clinical management strategy. MRI imaging has proven to be a useful troubleshooting tool that helps overcome false negatives in tumor response imaging after chemotherapy due to liver parenchyma changes. The purpose of this review is, therefore, to describe the characteristics of magnetic resonance imaging of the broad spectrum of liver damage induced by systemic chemotherapeutic agents in order to avoid misdiagnoses of liver metastases and disease progression and to define the most appropriate clinical management strategy.

Thyroglossal duct cysts and site-specific differential diagnoses: imaging findings with emphasis on ultrasound assessment

Thyroglossal duct cysts (TGDCs) are the most common congenital abnormality of the neck, accounting for approximately 70% of congenital neck lesions. Two-thirds of thyroglossal duct anomalies are diagnosed within the first three decades of life, with more than half being identified before 10 years of age. The age of presentation, clinical examination and imaging are essential for an accurate diagnosis. This review aims to summarize the imaging findings of TGDCs and their main differential diagnoses with emphasis on ultrasound assessment. A focus on site-specific key differentiating between them is also addressed.

Utility of a gel stand-off pad in the detection of Doppler signal on focal nodular lesions of the skin

PURPOSE

Gel pad is an aqueous, flexible, easy available, disposable spacer used for the ultrasound (US) scan of superficial or difficult-to-visualize areas. In clinical practice, it is widely used in B-mode US approach of superficial lesions but, to date, no data have been provided as to its efficacy in the Doppler detection of superficial flows. The aim of our study was to demonstrate the role of stand-off gel pad in the detection of the otherwise-missed peri- or intra-lesional flow signals on Doppler imaging.

MATERIALS AND METHODS

A total of 100 superficial lesions undergone to an US evaluation using a 7.5-12-MHz linear probe were evaluated prospectively with and without interposition of a gel stand-off pad to detect the presence or absence of vascularization and to classify the vascular pattern.

RESULTS

Peri- or intra-lesional flow was demonstrated in 56% of cases without and in 84% of cases with interposition of a gel stand-off pad; moreover, a statistically significant difference (p value < 0.001) was observed at Chi-square test in the identification of the flow pattern between the use and no use of the pad.

CONCLUSIONS

The use of a gel stand-off pad allows the detection of otherwise-missed peri- or intra-lesional flow signals on Doppler imaging, increasing the diagnostic role of this technique in differential diagnosis of superficial lesions.

Imaging findings of inflammatory pseudotumor-like follicular dendritic cell tumors of the liver: Two case reports and literature review

BACKGROUND

Inflammatory pseudotumor-like follicular dendritic cell (IPT-like FDC) tumors of the liver is an uncommon tumor with extremely low incidence. To date, the radiologic findings of this tumor in multiphase computed tomography (CT) and magnetic resonance imaging (MRI) imaging have not been described.

CASE SUMMARY

Patient 1 is a 31-year-old Chinese female, whose complaining incidentally coincided with the finding of multiple liver masses. In the local hospital, an abdominal enhanced CT found two hypo-dense solid lesions, with heterogeneous sustained hypoenhancement, in the upper segment of the liver’s right posterior lobe. In our hospital, enhanced magnetic resonance imaging (MRI) with hepatocyte-specific contrast agents showed a similar enhanced pattern of lesions with patchy hyperintensity in the hepatobiliary phase (HBP). The patient underwent surgery and recovered well. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found on the regular re-examination. Patient 2 is a 48-year-old Chinese male admitted to our hospital for a huge unexpected hepatic lesion. A dynamic enhanced abdominal CT revealed a huge heterogeneous enhanced solid tumor in the right lobe of the liver with a size of 100 mm × 80 mm, which showed a heterogeneous sustained hypoenhancement. In addition, enlarged lymph nodes were found in the hilum of the liver. This patient underwent a hepatic lobectomy and lymph node dissection. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found upon regular re-examination.

CONCLUSION

When a hepatic tumor shows heterogeneous sustained hypoenhancement with a patchy enhancement during HBP, an IPT-like FDC tumor should be considered in the differential diagnosis.

Noninvasive imaging diagnosis of sinusoidal obstruction syndrome: a pictorial review

Sinusoidal obstruction syndrome (SOS) is a rare liver disorder due to hepatic vascular injury. Its rapid and accurate diagnosis is crucial for patient survival. SOS is often established clinically, based on Baltimore, modified Seattle, or European Society for Blood and Marrow Transplantation (EBMT) criteria. Unfortunately, such criteria are not highly specificity and fail to provide a timely, reliable differential diagnosis. The use of noninvasive imaging techniques, such as ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), has recently grown in this setting, some key imaging features offering diagnostic improvement. This review provides a synopsis of current noninvasive imaging techniques used for this purpose, summarizing accurate and reliable diagnostic features of SOS.

Morphological and dynamic evaluation of complex cystic focal liver lesions by contrast-enhanced ultrasound: current state of the art

Complex cystic and cystic-like focal liver lesions (FLLs) encompass a spectrum of disorders ranging from non-neoplastic conditions to benign and malignant tumors. In this prospective, the possibility of non-invasive differentiation of these lesions is extremely important, because the clinical implications and therapeutic strategies vary considerably. Because of its advantageous cost/benefit ratio, widespread availability and easy execution, ultrasound (US) is the first-line imaging modality in most countries for the initial liver survey and represents the imaging technique that usually detects a complex liver cyst. However, US showed poor efficacy in the differential diagnosis of complex cystic FLLs. Thus, for years, computed tomography (CT) and magnetic resonance (MR) imaging have been used for further assessment of these lesions. Recently, the development of low mechanical index real-time contrast-enhanced ultrasound (CEUS) technique performed with the second generation of US contrast agents has led to an accurate depiction of macrovasculature and microvasculature. The technique yields information about contrast enhancement of the liver and FLLs almost as CT and MRI do, but in real time and without the use of ionizing radiation. To date, there is only a small amount of evidence about the role of CEUS in the less common setting of complex liver cysts. The aim of this review is to offer an up-to-date overview on the state of the art of CEUS in the study of the most common complex cystic focal liver lesions. To our knowledge, there are no literature comprehensive reviews on this topic.

Vanishing Tumor in a Liver Graft from a Hepatitis B Virus Surface Antigen-Positive Donor

We report a case of vanishing tumor considered as inflammatory pseudotumor (IPT) found in the liver after living donor liver transplantation (LDLT) from a hepatitis B virus surface antigen-positive donor. The radiological findings were similar to those of hepatocellular carcinoma (HCC). However, the tumor disappeared completely within several months and was suggested to have been an IPT. IPT is known to be associated with biliary duct operation or biliary infection, and it can show various enhancement patterns in radiological studies, sometimes resembling HCC. It should be considered in the differential diagnosis of a liver tumor in patients with LDLT.