Differentiating mass-forming intrahepatic cholangiocarcinoma from atypical hepatocellular carcinoma using gadoxetic acid-enhanced MRI.

AIM: To examine the differential features of mass-forming intrahepatic cholangiocarcinoma (ICC) from atypical hypovascular hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: The institutional review board approved this retrospective study and waived informed patient consent. Seventy patients with pathologically proven ICCs (35) and hypovascular atypical HCCs (35) who had undergone preoperative gadoxetic acid-enhanced MRI were enrolled in this study. Images were analysed for the shape of the lesions and presence of hyperintensity on the T1-weighted image (T1WI) and hypo- or hyperintense areas on the T2-weighted image (T2WI). In addition, images were analysed for the presence of linear hyperintensity or multifocal, tiny, hyperintense foci on T2WI and the presence of rim enhancement during early dynamic phases and a central enhancement with a hypointense rim (target appearance) on the 10 and 20 min hepatobiliary phase images. The significance of these findings was determined by the X(2) test. RESULTS: Univariate analysis revealed that the following significant parameters favour ICC or hypovascular HCC; the presence of T2 hypo- and hyperintense areas and target appearance on the 10 min hepatobiliary phase images favour ICC, and the presence of T2 linear hyperintensity and T2 multifocal hyperintense foci favour hypovascular HCC (p < 0.05). Multivariate analysis revealed that only target appearance on the 10 min hepatobiliary phase was predictive of ICC (p = 0.002) as 30 ICCs (85.7%) showed this feature. However, the target appearance was also observed in all six scirrhous HCCs. CONCLUSION: A target appearance on the 10 min hepatobiliary phase images is the best predictor for identifying mass-forming ICC at gadoxetic acid-enhanced MRI.

Brenner tumor of the ovary: CT and MR findings.

PURPOSE: The purpose of this study was to determine the CT and MR characteristics of Brenner tumors, rare epithelial neoplasms of the ovary. METHOD: CT and MR scans of eight pathologically proven Brenner tumors of the ovary (seven benign, one malignant, and one associated with mucinous cystadenoma) were retrospectively reviewed. The masses were analyzed for location, size, external configuration, internal architecture, enhancement pattern, presence of calcification, and metastatic spread. RESULTS: The patients' median age was 63 years (range 39-79 years), and the mean size of the tumors was 11.4 cm (7.5-17 cm). All tumors were unilateral and had a well-defined margin. The mass was mostly solid in three, mostly cystic in one, and "mixed" solid and cystic in four cases. The tumors with cystic components (n = 5) were mostly multilocular in appearance (n = 4). All the solid components showed mild homogeneous enhancement on postcontrast CT and MRI. Extensive amorphous calcification within the solid component on CT was seen in five of six cases (83%). No characteristic findings discriminating malignancy from benign Brenner tumor could be found. CONCLUSION: Extensive amorphous calcification in a solid mass or solid component in a multilocular cystic mass is a characteristic finding of Brenner tumor of the ovary on CT and MRI.

Radiologic findings of renal hemangioma: report of three cases.

Renal hemangioma is an uncommon benign tumor which usually causes painless or painful gross hematuria. Its preoperative diagnosis is extremely difficult or even impossible. We experienced three cases of renal hemangioma, located mainly at the pelvocalyceal junction or in the inner medulla. US demonstrated variable echogenecity, and CT revealed a lack of significant enhancement. Where there is gross hematuria in a young adult, especially when the renal mass located in the pelvocalyceal junction or inner medulla shows little enhancement on CT, renal hemangioma should form part of the differential diagnosis.

CT features of torsion of benign cystic teratoma of the ovary.

PURPOSE: The purpose of this work was to evaluate the usefulness of CT scans for distinguishing torsed from uncomplicated benign cystic teratoma (BCT). METHOD: Retrospective analysis was performed in 14 torsed BCTs (14 patients) and in 23 uncomplicated BCTs (20 patients) for comparison. The features on CT scans were compared to the pathologic findings. RESULTS: CT findings indicating torsed BCT were the presence of eccentric wall thickening of >1 cm, peritumoral infiltration, and presence of enlarged solid tubal mass adjacent to the uterus (p < 0.05). CONCLUSION: The present study suggests that CT is useful in differentiating torsed from uncomplicated BCT. Although CT findings are not specific for some patients, detection of certain CT findings could increase the diagnostic accuracy.

MR imaging of primary uterine lymphoma.

Primary malignant lymphoma of the uterus is a rare disease. We present the MR findings in three cases where the uterus was the initial site. MR findings wer retrospectively evaluated. Although the intact junctional zone is a specific finding for lymphoma, diffuse enlargement of the uterus and relatively homogeneous signal intensity on MR imaging in spite of large tumor size are helpful for diagnosing uterine lymphoma.