Hepatic schwannoma:Imaging findings on CT,MRI and contrast-enhanced ultrasonography

A primary benign schwannoma of the liver is extremely rare and is difficult to preoperatively discriminate from a malignant tumor.We compared the imaging and pathological findings,and examined the possibility of preoperatively diagnosing a benign liver schwannoma.A 72-year-old woman was admitted to our hospital because of a 4.6-cm mass in the liver.A malignant tumor was suspected,and a right hepatectomy was performed.After this,the diagnosis of a primary benign schwannoma of the liver was made through pathological examination.Contrast-enhanced ultrasonography(CEUS) with Sonazoid showed minute blood flows into the septum and solid areas of the tumor in the vascular phase;most likely due to increased arterial flow associated with infiltration of chronic inflammatory cells.In the postvascular phase,CEUS showed contrast defect of cystic areas and delayed enhancement of solid areas;most likely due to aggregation of siderophores.Because discriminating between a benign and malignant schwannoma of the liver is difficult,surgery is generally recommended.However,the two key findings from CEUS may be useful in discriminating ancient schwannoma by recognizing the hemorrhage involved in the secondary degeneration and aggregation of siderophores.

Evaluation of sorafenib for hepatocellular carcinoma by contrast-enhanced ultrasonography:A pilot study

AIM:To determine the usefulness of arrival time parametric imaging(AtPI) using contrast-enhanced ultrasonography(CEUS) with Sonazoid in evaluating early response to sorafenib for hepatocellular carcinoma(HCC).METHODS:Fourteen advanced HCC patients who received sorafenib 400/800 mg/d for at least 4 wk and were followed up by CEUS were enrolled in this study.CEUS was performed before treatment and 2 and 4 wk after treatment,and images of the target lesion in the arterial phase were recorded for each patient.The images were analyzed by AtPI.Color mapping(CM) images obtained by AtPI were compared before and after the treatment.In these CM images,the mean arrival time of the contrast agent in the region of interest from the starting point [mean time(MT)] was calculated.In each patient,differences between MT before and MT 2 and 4 wk after the treatment were compared with responses evaluated 4-8 wk after the treatment by dynamic computed tomography(CT),and statistical analysis was performed.Modified response evaluation criteria in solid tumors was used for the response evaluation.RESULTS:In CM images both 2 and 4 wk after the treatment,delays in the arrival time of the contrast agent were noted in 8 of the 14 patients.In the other 6 patients,no color changes were observed in the tumor,or red and/or yellow increase,suggesting a decrease in blood flow velocity between images 2 and 4 wk after the treatment and those before the treatment.Dynamic CT could be performed 4-8 wk after the treatment in 13 of the 14 patients.Median differences in the MT were 1.13 s and 1.015 s,2 and 4 wk after the treatment,respectively,in the 8 patients who showed stable disease(SD)/partial response(PR) on dynamic CT.Median differences in the MT were-0.39 s and-0.95 s,2 and 4 wk after the treatment,respectively,in the 5 patients who showed progressive disease(PD).Differences in the median MT between SD/PR and PD groups were significant 2 and 4 wk after the treatment with P = 0.019 and P = 0.028,respectively.CONCLUSION:AtPI by CEUS using Sonazoid is suggested to be useful for evaluating early responses to sorafenib.