Diagnosis of Hepatic Angiomyolipoma by Combination of Baseline and Contrast-Enhanced Ultrasound--A Prospective Study in Non-Cirrhotic Patients

Objectives

Hepatic angiomyolipoma (HAML) is a rare, benign mesenchymal tumor of the liver and its diagnosis has been considered challenging. The aim of this study was to investigate prospectively the diagnostic efficacy of the incorporation of both baseline ultrasound (US) and contrast-enhanced ultrasound (CEUS) features of HAML in patients without cirrhosis.

Materials and Methods

Consecutive 1748 non-cirrhotic patients with focal liver lesions (FLLs) were prospectively enrolled. Baseline US and CEUS were performed before resection or biopsy. Ultrasound imaging diagnosis of FLLs was compared with the pathological results.

Results

Final diagnoses were established in 41 patients with HAML (2.3%) with normal alpha fetal protein (AFP) level and in 1707 patients with FLL other than HAML. Diagnostic criteria for HAML was based on the combination of baseline US and CEUS appearance of the nodule: (1) Well-defined, marked hyper-echoic nodule without surrounding hypo-echoic halo on baseline US; (2) hyper-enhancement in the arterial phase (exclude initial peripheral nodular enhancement and spoke-wheel arteries) and remains hyper-enhancement or iso-enhancement in the late phase. The diagnostic criteria were fulfilled in 31 HAMLs, 1 hepatocellular adenoma and 1 hemangioma. Ten HAMLs were misdiagnosed as other liver tumors because they did not meet the diagnostic criteria mentioned above and consequently yielded a sensitivity, specificity, positive predictive values, negative predictive values and Youden index of 75.61%, 99.88%, 93.94%, 99.42%, and 0.75 respectively.

Conclusion

The combination of baseline US and CEUS may lead to the correct diagnosis noninvasively in the majority of HAMLs in non-cirrhotic patients with normal AFP level.

Hepatic angiomyolipomas: ultrasonic characteristics of 25 patients from a single center

Twenty-five pathologically proven hepatic angiomyolipomas (AMLs) were included in the study. Ultrasonic features of hepatic AMLs were reviewed. Three types of echogenicity were observed on ultrasound examination: (i) strong hyper-echogenicity, (ii) moderate hyper-echogenicity and (iii) hypo-echogenicity. Vascular signals within tumors could be detected in 22 (88.00%) tumors as multiple punctiform, filiform or dendriform signals by color Doppler flow imaging. Based on the enhancement patterns in the arterial, portal and late phases, the features of hepatic AMLs on contrast-enhanced ultrasound were divided into four subtypes: (i) "fast in slow out" (68.00%, n = 17); (ii) "fast in same out" (16%, n = 4); (iii) "fast in fast out" (12.00%, n = 3); and (iv) "fast in uneven out" (4.00%, n = 1). Contrast-enhanced ultrasound diagnosed 22 (88.00%) tumors as benign tumors and 13 (52.00%) as hepatic AMLs. Four cases were misdiagnosed as hepatic hemangioma, five cases as focal nodular hyperplasia (total = 36.00%). The rate of correct diagnosis of hepatic AMLs increased significantly from 24.00% for ultrasound alone to 52.00% for contrast-enhanced ultrasound. Therefore, information obtained from ultrasound, color Doppler flow imaging and contrast-enhanced ultrasound should be combined to improve diagnosis.

Acoustic radiation force impulse elastography in differentiating renal solid masses: a preliminary experience

New diagnostic methods are required to diagnose renal mass. Thus, we assessed virtual tissue quantification (VTQ) of acoustic radiation force impulse (ARFI) elastography in differentiation of renal solid masses. Forty-two patients with renal masses were assessed by VTQ in terms of measurement of the shear wave velocity (SWV). The masses were divided into three groups. They were clear cell carcinoma (CCC) angiomyolipoma (AML), and pseudotumor. The differences among the three groups in SWV, as well as between masses and its surrounding parenchyma, were investigated. Receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic performance. We found that the SWV among the three groups were significant different (F = 6.976, P = 0.003) and the SWV of pseudotumor (3.14 ± 0.75 m/s) was significantly higher than CCC (2.46 ± 0.45 m/s) and AML (2.49 ± 0.63 m/s) (P = 0.007 and 0.001 respectively). There were no significant difference between CCC and AML in SWV (P = 0.719). For each group, there was no significant difference between the mass and its surrounding parenchyma (P = 0.693, 0.892, and 0.714, respectively). Between pseudotumor and CCC, the optimal cut-off value of SWV for differential diagnoses was 3.07 m/s; and the area under the ROC curve (AUC) was 0.78 (95% CI: 0.560 to 0.924) (P = 0.004), the sensitivity and specificity were 100% and 58.3%, respectively. Between pseudotumor and AML, the optimal cut-off value of SWV for differential diagnoses was 3.03 m/s, thus AUC curve was 0.786 (95% CI: 0.591 to 0.918) (P = 0.002), the sensitivity and specificity were 100% and 58.3%, respectively. No significant difference was found between AML and CCC (P = 0.587) and the AUC was 0.562. To conclude, our results support that ARFI has potential value in differentiation between CCC and pseudotumor, or between AML and pseudotumor, however, it fails to make a distinction between CCC and AML.

Multi-slice computed tomography manifestations of hepatic epithelioid angiomyolipoma

AIM: To explore the characteristics of multi-slice computed tomography (CT) manifestations of hepatic epithelioid angiomyolipoma (HEA), improve the rate of accurate diagnosis, and reduce the misdiagnostic rate.

METHODS: The multi-slice CT manifestations in five patients who were diagnosed with HEA definitely by postoperative pathological examination were analysed retrospectively. Three female patients and two male patients were included. Before operation, four patients received plain CT scanning and dynamic enhancement scanning, and the other patient only received enhancement scanning, with immunohistochemical analysis conducted after postoperative pathological examination. Four patients were misdiagnosed by CT, including three patients misdiagnosed with hepatic cell carcinoma and one patient with focal nodular hyperplasia.

RESULTS: Upper abdominal multi-slice spiral CT scanning and three-stage enhancement scanning were conducted in five patients with HEA before operation. HEA had certain characteristic CT manifestations: low density masses, a few relatively high-density masses or fat-density masses diffusely shown in foci, clear boundary, round or oval and large focus, and tumour size ranging from 3.1 cm × 2.5 cm to 7.0 cm × 5.2 cm. During enhancement scanning, the foci were significantly enhanced uniformly or non-uniformly during the arterial phase, while during the venous and equilibrium phases, the foci were enhanced continuously or showed obvious low-density masses. Obviously enhanced and widened vessels could be found adjacent to foci or in the central area of foci during the arterial phase.

CONCLUSION: CT manifestations of HEA have certain characteristics. Primary diagnosis can be obtained by combining CT findings with clinical data, but pathological examination is still needed for a definite diagnosis.

Study of 320-slice dynamic volume CT perfusion in different pathologic types of kidney tumor: preliminary results

Objective

To investigate microcirculatory differences between pathologic types of kidney tumor using 320-slice dynamic volume CT perfusion.

Methods

Perfusion imaging with 320-slice dynamic volume CT was prospectively performed in 85 patients with pathologically proven clear cell renal cell carcinoma (RCC) (n = 66), papillary RCC (n = 7), chromophobe RCC (n = 5), angiomyolipoma (AML) with minimal fat (n = 7), or RCC (n = 78). Equivalent blood volume (Equiv BV), permeability surface-area product (PS; clearance/unit volume = permeability), and blood flow (BF) of tumor and normal renal cortex were measured and analyzed. Effective radiation dose was calculated.

Results

There was a significant difference in all three parameters between tumor and normal renal cortex (P<0.001). Equiv BV was significantly different between RCC and AML with minimal fat (P = 0.038) and between clear cell RCC and AML with minimal fat (P<0.001). Mean Equiv BV and BF were significantly higher in clear cell RCC than in papillary RCC (P<0.001 for both) and mean Equiv BV was higher in clear cell RCC than in chromophobe RCC (P<0.001). The effective radiation dose of the CT perfusion protocol was 18.5 mSv.

Conclusion

Perfusion imaging using 320-slice dynamic volume CT can be used to evaluate hemodynamic features of the whole kidney and kidney tumors, which may be useful in the differential diagnosis of these four pathologic types of kidney tumor.

Angiomyolipoma presenting as renal abscesses: a consideration for further evaluation of renal abscess

AIMS AND OBJECTIVES

This is to describe an usual presentation of renal angiomyolipoma as renal abscess

CASE REPORT

This is a case report of a 51 year old man with clinical and radiological features suggestive of renal abscess. The patient had exploratory laparatomy and a simple nephrectomy for a non functioning kidney which was more like a bag of pus. The histological report however revealed renal abscess coexisting with angiomyolipoma supporting previous reports that renal abscess may be a harbinger of other renal pathologies.

CONCLUSION

Abscesses are usually managed by drainage and the dictum of 'wherever there is pus let it out' holds generally but this does not always suffice in renal abscesses because renal abscesses are often found in the background of other diseases which may be of more clinical importance.

Defining vascular signatures of benign hepatic masses: role of MDCT with 3D rendering

Multidetector CT (MDCT) provides new opportunities for hepatic tumor characterization. By coupling high-resolution isotropic datasets with advanced post-processing tools, maps of tumor vascularity can be generated to elucidate characteristic findings. This two-part review describes a range of benign and malignant liver masses, with emphasis on IV contrast-enhanced MDCT features and vascular signatures that can be identified on 3D vascular mapping.

Differentiation of clear from non-clear cell renal cell carcinoma using CT washout formula

INTRODUCTION

To further elucidate potential patterns of contrast enhancement for renal neoplasm subtypes, we investigated utility of contrast washout formula to differentiate renal tumor histology after multiphase computerized tomography (CT).

MATERIALS AND METHODS

Single center retrospective cohort study of 163 patients with multiphase CT for renal masses obtained October 2007 to July 2012. Pathology confirmed clear cell (CC-RCC; n = 92), papillary (Pa-RCC; n = 43), chromophobe (Ch-RCC; n = 6), oncocytoma (OC; n = 11), or angiomyolipoma (AML; n = 11) histology. Two radiologists in consensus and blinded to histology recorded tumor size, morphology, and attenuation measurements in Hounsfield Units (HU). Data were analyzed between subgroups based on histology. Enhancement washout of the tumor was calculated by the formula (Mass nephrographic HU-Mass delayed HU)/(Mass nephrographic HU-Mass non-contrast HU) and used to calculate sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Tumor size was largest among CC-RCC (p < 0.001). Homogeneous composition was more common among Pa-RCC and Ch-RCC (p < 0.001). Median washout for Ch-RCC (0.27) was significantly different from that of OC (0.54, p = 0.05). Overall 25 (15.3%) of tumors had washout < 0. Tumors with washout value < 0 were Pa-RCC 24/43 (56%), and Ch-RCC 1/6 (14%). Washout value < 0 had a specificity of 99.2% for Pa-RCC and 100% for non-CC-RCC. Washout value ≥ 0 had a sensitivity and NPV of 100% for CC-RCC, OC, and AML. Washout value ≥ 0 had a specificity of 35.2% and a PPV of 66.7% for CC-RCC.

CONCLUSIONS

Enhancement washout value < 0 is highly specific for Pa-RCC and non-CC-RCC. Washout value ≥ 0 is highly sensitive for CC-RCC, OC, and AML while there was a significant difference in median washout between OC and Ch-RCC. Further prospective investigation is requisite to confirm these findings.

Angiomyolipoma with minimal fat: differentiation from papillary renal cell carcinoma by helical CT

AIM

To evaluate whether helical computed tomography (CT) images can be used to differentiate angiomyolipomas (AMLs) with minimal fat from papillary renal cell carcinomas (PRCCs) based on their morphological characteristics and enhancement features.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board. Informed consent was waived. Forty-four patients (21 with AMLs with minimal fat and 23 with PRCCs) who underwent enhanced helical CT before total or partial nephrectomy were included. Two radiologists, who were blinded to the histopathology results, read the CT images and recorded the attenuation value, morphological characteristics, and enhancement features of the tumours, which were subsequently evaluated. An independent samples t-test, χ(2) test, and rank sum test were performed between the tumours. The predictive value of a CT finding was determined by multivariate logistic regression analysis.

RESULTS

AML with minimal fat had an apparent female prevalence (p < 0.01). Intra-tumoural vessels were noted in 11 cases of AML with minimal fat and three PRCC cases (p < 0.01). The unenhanced attenuation characteristic was significantly different between the two diseases (p < 0.001). The absolute attenuation values (AAVs) and the corrected attenuation values (CAVs) of the AML with minimal fat group of unenhanced and two phases of enhanced images were greater compared with that of the PRCC group (p < 0.05). After contrast medium injection, the tumour enhancement value (TEV) of the AML with minimal fat group in the corticomedullary phase was greater than that of the PRCC group (p < 0.01). Most cases of both tumour types demonstrated early enhancement characteristics; the enhancement value of the AML with minimal fat group was greater compared with that of the PRCC group (p < 0.01). The unenhanced attenuation characteristic, intra-tumoural vessels, and CAVs of unenhanced and early excretory phase scans were valuable parameters to differentiate between AML with minimal fat and PRCC tumours by multivariate logistic regression analysis (p < 0.05 for all).

CONCLUSION

The unenhanced attenuation characteristic, intra-tumoural vessels, and the attenuation values of unenhanced and early excretory phase scans are valuable parameters in differentiating AML with minimal fat from PRCC at CT.

Renal angiomyolipomas in tuberous sclerosis--rare but potentially life-threatening lesions

We discuss an 18-year-old girl, diagnosed with tuberous sclerosis complex and known to have renal angiomyolipomas (AMLs) but having no regular urological follow-up, who presented with left-sided abdominal pain and haematuria on urine dipstick testing at the out-of-hours General Practitioner (GP) service. She was diagnosed as having urinary tract infection/pyelonephritis and discharged with simple analgesia and antibiotics. Subsequent imaging of her renal tract demonstrated multiple large AMLs with evidence of recent bleeding, which required arterial embolisation.

Bilateral renal masses: pathologic concordance and impact of temporal presentation

AIM

The aim of this paper was to evaluate the pathologic concordance of bilateral renal masses and the influence of synchronous or asynchronous occurrence on patient long term survival.

METHODS

Thirty-one consecutive patients with bilateral synchronous (N.=17, 55.0%) or asynchronous (N.=14, 45.0%) renal masses were retrospectively reviewed from January 2000 to December 2010. We included all patients with confirmed diagnosis on pathologic examination of a specimen or a percutaneous biopsy and evidence of angiomyolipoma on CT. Survival was assessed using the Kaplan-Meier method. RESULTS. The first lesion was larger than the second (60 vs. 30 mm, P<0.001). Pathologic concordance rate between tumors was 87.1%. A clear cell carcinoma was associated with a papillary carcinoma in 3.2%, and an angiomyolipoma in 6.4%. Median time of occurrence of a metachronous lesion was 50 months (IQR: 24; 92). Disease-free survival at 5 and 10 years was 87.2% and 78.5%. No statistical difference in disease free survival was observed between synchronous and metachronous tumors. conclusion: Discordant pathology between bilateral renal masses is uncommon, with a slight probability of benign tumor. Occurrence of a metachronous tumor can exceed 10 years.

Minimal fat renal angiomyolipoma: the initial study with contrast-enhanced ultrasonography

We visualized minimal fat renal angiomyolipomas (AMLs) by contrast-enhanced ultrasonography (CEUS). Conventional ultrasound and CEUS images were retrospectively analyzed for solid minimal fat renal AML cases (n = 18) and solid renal cell carcinoma (RCC) cases (n = 105). We compared size, echogenicity and color flow signals with conventional ultrasound, and enhancement patterns with CEUS, in AMLs vs. RCCs. No significant differences in echogenicity and color flow signal existed between AMLs and RCCs using conventional ultrasound. With CEUS, slow centripetal enhancement in the cortical phase (83.3% of AMLs vs. 1.9% of RCCs) and homogeneous peak enhancement (100.0% of AMLs vs. 34.3% of RCCs) were valuable traits for differentiating these tumor types. These two CEUS-determined traits, combined, were differentiating criteria for minimal fat renal AMLs and RCCs; positive and negative predictive values were 100.0% and 97.2%, respectively. Slow centripetal enhancement in the cortical phase and homogeneous enhancement at peak are main features of CEUS-confirmed solid minimal fat renal AML.

Epithelioid angiomyolipoma presenting as an urothelial

OBJECTIVE

Renal angiomyolipoma is a mesenchymal neoplasm composed of dysmorphic blood vessels, smooth muscle, and adipose tissue. Epithelioidangiomyolipoma is an uncommon variant considered potentially malignant. We report a case of renal epithelioid angiomyolipoma suspicious for urothelialcarcinoma of renal pelvis.

METHODS

A 50-year-old woman with a 3-day history of macroscopic hematuria and CT-scan showing a tumor arising from the left renal pelvis suspicious for urothelialcarcinoma. Nephrectomy was analysed in multiple slides of hematoxilin-eosin and immunohistochemistry.

RESULTS

Left nephrectomy was performed. Tumor sized 8 cm and showed pathologic findings of epithelioid angiomyolipoma with a little component of classic angiomyolipoma. We studied differential diagnosis and pathologic characteristics for the prognosis.

CONCLUSIONS

Pathologic study in detail is fundamental for differential diagnosis and prognosis of this tumor. Our patient's pathology showed good prognosis, however follow-up is important due the malignant potential of the neoplasm.

Hepatic angiomyolipoma: a series of six cases with emphasis on pathological-radiological correlations and unusual variants diagnosed by core needle biopsy

Hepatic angiomyolipoma is rare and may pose differential diagnostic difficulty, particularly if encountered in core needle biopsy. We studied 6 cases from 5 males and one female (median age, 48.6 yrs). All presented with non-specific symptoms or an incidentally discovered tumor mass. Two patients had a remote history of chemotherapy for hematological neoplasms (acute lymphoblastic leukemia and Hodgkin lymphoma respectively) and another had clear cell renal cell carcinoma and anaplastic pancreatic carcinoma diagnosed at autopsy without definable syndrome. None of the patients had evidence of the tuberous sclerosis complex or renal or other extra-renal angiomyolipoma. Three tumors were resected completely and three have been only biopsied and followed up. None of the resected cases recurred at a mean follow-up of 35 months. Histologically, tumors were classified as classical triphasic (1), lipomatous (2), epithelioid/oncocytoid (1), epithelioid trabecular (1) and myelolipoma-like (1). The adjacent liver parenchyma was normal in 3 cases, showed pigment cirrhosis in one case and mild fatty change in another case. One case had clinically diagnosed but histologically unverified cirrhosis. The initial diagnostic impression/frozen section was misleading in 5 of the cases and included vascular lesion, focal fatty change, myelolipoma, hepatocellular tumor and oncocytic neoplasm. All tumors expressed HMB45 and variably desmin. One epithelioid lesion expressed HMB45 and TFE3, but lacked desmin expression. In conclusion, hepatic angiomyolipomas are increasingly recognized as incidental findings during surveillance for cirrhosis or investigations for unrelated conditions. Awareness of their diverse morphological spectrum in liver biopsy is necessary to avoid misdiagnosis as hepatocellular carcinoma, metastatic melanoma or other malignant neoplasms.

Bibliographic review about the usefulness of ultrasound contrast media in the study of renal masses

OBJECTIVES

The microbubbles enhanced ultrasound contrast is a novel technique that informs us in real time of renal perfusion and microcirculation.

METHOD

We reviewed the literature about its use in the study of renal masses in order to show their actual clinical performance in this condition.

RESULT

This technique is useful in the differential diagnosis of pseudotumors, characterization and monitoring of small renal masses, the study of complex renal cysts and controlling the progression of renal masses that underwent ablative treatments. Like any diagnostic technique has some limitations on usage;its rapid contrast wash, being operator-dependent, require some experience and need special software to be correctly interpreted.

CONCLUSIONS

The microbubbles enhanced ultrasound contrast is a useful and economic technique for the study and differential diagnosis of the renal masses.

[A case of renal angiomyolipoma with tumor thrombus]

A 42-year-old woman presented with left renal tumor. Computed tomography showed a left renal tumor (6 cm in diameter) and a tumor thrombus at the left renal vein, which had equal density to fat tissue. She was diagnosed with malignant tumor, and underwent radical left nephrectomy and resection of thrombus. Pathological diagnosis was angiomyolipoma with no findings of malignancy. No signs of recurrence or metastasis have been observed for 8 months after the operation.

Angiomyolipoma with vascular invasion during pregnancy

Angiomyolipoma (AML) is a rare, benign tumor composed of fat cells, smooth muscle cells, and blood vessels. They are commonly found in the kidney but have also been reported to occur in the liver, ovary, fallopian tube, spermatic cord, palate, and colon. Most often, they are discovered as an incidental finding on computed tomography scan and remain inconsequential; however, certain characteristics such as size, presence of aneurysms, and location can transform this disease process into a life-threatening entity. Here, we describe the case of a 30-year-old pregnant woman with bilateral renal AMLs in which there was invasion of the right renal vein and extension of the tumor into the inferior vena cava. The patient was believed to be at significant risk of hormone-mediated rapid expansion, embolization, and life-threatening pulmonary embolus during the pregnancy and was taken to the operating room for right nephrectomy and removal of the tumor from the vena cava. We report the first case of elective nephrectomy with the removal of the tumor from vena cava complicating pregnancy. The major risks of rupture, spontaneous hemorrhage, renal failure, and tumor thrombus were avoided, thereby demonstrating that despite pregnancy, successful surgery can be performed during the second trimester for the management of complicated AMLs.

Prophylactic embolization of renal angiomyolipomas: evaluation of therapeutic response using CT 3D volume calculation and density histograms

PURPOSE

To evaluate the efficacy and tolerance of prophylactic embolization of angiomyolipomas (AMLs) and to analyze the therapeutic response by using three-dimensional 3D volume calculation and 3D quantification of fatty and angiomyogenic components during computed tomography (CT) follow-up.

MATERIALS AND METHODS

Over a 51-month period, 30 patients with 34 AMLs (mean diameter, 82 mm ± 37; range, 30-173 mm) underwent 37 prophylactic embolization procedures. The protocol included supraselective arterial embolization with a combination of absolute alcohol, microparticles, and coils. Mean clinical and imaging follow-up were 20.5 and 14.5 months, respectively. The 3D volume calculation and density histograms were retrospectively analyzed for treatment evaluation.

RESULTS

Four technical failures were observed (11%), with one successful secondary reattempt, resulting in 31 AMLs (91.2%) being embolized. Thirty (88.2%) had CT follow-up and were included in the analysis. Embolization was complete after a single procedure for 25 AMLs (83%) and required two procedures in two cases. Three AMLs had incomplete embolization and were scheduled for a second procedure. Mean volume reductions were 43% ± 32 for AMLs followed for 1-6 months after embolization and 81% ± 19 for the 12 AMLs followed for more than 1 year. The volume reduction after embolization was significantly correlated with the AML initial composition, with fat-rich AMLs showing a much smaller reduction of size than predominantly angiomyomatous AMLs (P < .05).

CONCLUSIONS

Prophylactic embolization allows significant reduction of AML volume with a high success rate. Three-dimensional CT volume and density histogram calculations suggest that it is especially effective on angiomyogenic components and fat-poor AMLs.