Innovative Ultraschalldiagnostik bei Nierentumoren

Primary renal malignant epithelioid angiomyolipoma with distant metastasis: a case report and literature review

Epithelioid angiomyolipoma (EAML) is a rare type of mesenchymal angiomyolipoma with potential malignancy in the kidney that can cause lymph node metastases, local recurrence, and distant metastases. Herein, we describe a case of EAML in the right kidney of a 51-year-old man who was admitted to the hospital with a right abdominal mass. Computed tomography revealed a heterogeneously enhanced mass with blurred margins, which was considered a malignant tumor. A radical nephrectomy was then performed. Two years later, the patient developed liver metastases from EAML and was administered sintilimab combined with bevacizumab. The patient survived after 6 months of follow-up. Histologically, the tumors showed clear boundaries and no obvious capsules. The tumor tissue mainly consisted of epithelioid tumor cells, thick-walled blood vessels, and a small amount of adipose tissue. Tumor cells with lipid vacuoles and acinar areas were large, round, polygonal, eosinophilic, or transparent in the cytoplasm. The enlarged and hyperchromatic nuclei were accompanied by distinct nucleoli and pathological mitosis. These histopathological findings resembled those of renal cell carcinoma, and immunohistochemical analysis was performed. The tumor cells were diffusely positive for HMB45, Melan-A, CK20, vimentin antibodies, and TFE3, suggesting that the tumor originated from perivascular epithelioid cells, excluding renal cell carcinoma. The Ki-67 index was 10%. These histopathological features were observed in liver mass puncture tissues. We also summarized 46 cases of EAML with distant metastasis and explored the clinicopathological features of EAML to improve the treatment of the disease. EAML is often ignored in the clinical setting, leading to metastasis and recurrence. Therefore, EAMLs require long-term follow-up, and timely detection of recurrent disease can improve the prognosis.

Comparative diagnostic performance of contrast-enhanced ultrasound and dynamic contrast-enhanced magnetic resonance imaging for differentiating clear cell and non-clear cell renal cell carcinoma

OBJECTIVE

To compare the diagnostic efficiency of contrast-enhanced ultrasound (CEUS) with that of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the differential diagnosis of clear and non-clear cell renal cell carcinoma, as confirmed by subsequent pathology.

METHODS

A total of 181 patients with 184 renal lesions diagnosed by both CEUS and DCE-MRI were enrolled in the study, including 136 clear cell renal cell carcinoma (ccRCC) and 48 non-clear cell renal cell carcinoma (non-ccRCC) tumors. All lesions were confirmed by histopathologic diagnosis after surgical resection. Interobserver agreement was estimated using a weighted kappa statistic. Diagnostic efficiency in evaluating ccRCC and non-ccRCC was compared between CEUS and DCE-MRI.

RESULTS

The weighted kappa value for interobserver agreement was 0.746 to 0.884 for CEUS diagnosis and 0.764 to 0.895 for DCE-MRI diagnosis. Good diagnostic performance in differential diagnosis of ccRCC and non-ccRCC was displayed by both CEUS and DCE-MRI: sensitivity was 89.7% and 91.9%, respectively; specificity was 77.1% and 68.8%, respectively; and area under the receiver operating curve was 0.834 and 0.803, respectively. No statistically significant differences were present between the two methods (p = 0.54).

CONCLUSIONS

Both CEUS and DCE-MRI imaging are effective for the differential diagnosis of ccRCC and non-ccRCC. Thus, CEUS could be an alternative to DCE-MRI as a first test for patients at risk of renal cancer, particularly where DCE-MRI cannot be carried out.

KEY POINTS

• CEUS and DCE-MRI features can help differentiate ccRCC and non-ccRCC. • The differential diagnosis of ccRCC and non-ccRCC by CEUS is comparable to that of DCE-MRI. • Interobserver agreement is generally high using CEUS and DCE-MRI.

[Clinical ultrasound in nephrology]

When used correctly, modern ultrasound diagnostics are helpful for the nephrologist especially in emergency situations on the ward, in dialysis and in the emergency admission to quickly make the correct diagnosis or as a diagnostic gatekeeper to initiate the correct next diagnostic and therapeutic steps in a time-saving manner. In addition to conventional B‑mode/gray scale sonography and Doppler sonography, new ultrasound transducers with higher spatial resolution and above all contrast agent sonography have significantly expanded the technical possibilities and help nephrologists and internists to answer diagnostic and clinical questions. This particularly applies to the kidneys, which up to now could only be clarified by means of contrast-enhanced computed tomography or magnetic resonance imaging. This will allow the nephrologist in 2021 to amalgamate the clinical symptoms, imaging results and pathophysiological knowledge in an ideal, time-saving manner for the benefit of the patient.

Routine or enhanced imaging to differentiate between type 1 and type 2 papillary renal cell carcinoma

AIM

To investigate imaging features and differentiating qualities of type 1 and type 2 papillary renal cell carcinoma (pRCC) by different imaging techniques.

MATERIALS AND METHODS

From 2007 to 2019, 107 patients with type 1 pRCC (T1-pRCC) and 147 with type 2 pRCC (T2-pRCC) were included in this retrospective study. All patients underwent conventional ultrasound (US); some also underwent contrast-enhanced ultrasound (CEUS), contrast-enhanced computed tomography (CECT), or contrast-enhanced magnetic resonance imaging (CE-MRI). Tumour Fuhrman grade or World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grade (after June 2016) and invasive ranges were recorded. The two types of pRCC were analysed and compared for imaging features including tumour position, size, margin, echo type, and colour Doppler flow imaging (CDFI) using US as well as enhanced features from CEUS, CECT, or CE-MRI.

RESULTS

T2-pRCC showed a higher Fuhrman grade (p<0.001) and greater propensity to invade extrarenal tissue (p<0.001) than T1-pRCC. On US imaging, T2-pRCC was more likely to be a cystic-solid lesion (p<0.001), and colour flow with a higher resistance index (RI; p=0.014) was more easily detected (p=0.001) in T2-pRCC than in T1-pRCC. Within contrast-enhanced examinations, more T2-pRCC lesions had blurred tumour borders (p=0.003), hypervascular characteristics (p=0.003), and heterogeneous enhancement (p<0.001) than those of T1-pRCC.

CONCLUSIONS

T2-pRCC manifests more aggressively than T1-pRCC. T2-pRCC has a higher proportion of hypervascular and heterogeneous enhancement than T1-RCC.

Contrast-Enhanced Ultrasonography as a Novel Method for the Dynamic Visualization of Blood Flow and Fiber Blockage in Dialyzers: A Feasibility Study

The capillary dialyzer represents the central element of the extracorporeal blood circuit of a therapy system for hemodialysis. The aim of this study was to assess the blood-flow characteristics of dialyzers with the help of modern ultrasound techniques. Five brand-new dialyzers (FX80 classix, Fresenius Medical Care, Bad Homburg, Germany) and five dialyzers after a dialysis session were analyzed by different ultrasound techniques to detect functional and structural changes. B-mode and Doppler techniques were not suitable to describe differences in brand-new and clinically applied dialyzers. Contrast-enhanced ultrasonography, however, was able to visualize blood-flow profiles in the capillaries. Although dialyzers displayed no signs of clinical dysfunction, contrast-enhanced ultrasonography was able to detect blocked capillaries of varying degrees after a dialysis session in all five examined dialyzers. Consequently, the blood-flow velocity was higher in the remaining unblocked capillaries in comparison to the velocity in the brand-new dialyzers. This information may be helpful for improving the geometric design of dialyzers, including their capillary membranes, and optimizing anti-coagulation strategies in hemodialysis patients.

[CME Sonography 89: Differential Diagnosis of Kidney Masses]

CME Sonography 89: Differential Diagnosis of Kidney Masses Abstract. Cystic and solid renal lesions are common in ultrasound diagnostics. The solid pseudotumor of the kidney, the so-called renal parenchymal cone, is found in up to 50 % of patients. Pathologically-anatomically it is either a hypertrophy of the column of Bertini or the entire renal lobus, which is located in the renal sinus. Renal cysts were found in a dissected section in 50 % of those over 50 years old. The cystic lesions are subdivided into five categories with the Bosniak classification. This classification is possible with CECT, CEMR and CEUS. The solid lesions are also evaluated by these methods, but the distinction is more difficult here. By measuring the echo intensity in ultrasound, the differentiation of the hyperechoic angiomyolipomas from other solid tumors and pseudotumors is possible. In color-coded Doppler sonography (CCDS), the clear-cell renal cell carcinoma (RCC) is often depicted with many tumor vessels, the remaining tumors with few or only single vessels. In CEUS and TIC, this tumor is shown to be highly perfused, and the influx in the TIC is often faster and stronger than in the surrounding healthy renal cortex. The other tumors are mostly perfused to a lesser extent, especially the papillary carcinomas are significantly less perfused than the renal cortex.