Early venous return in hepatic angiomyolipoma due to an intratumoral structure resembling an arteriovenous fistula.

Early venous return (EVR) is an important radiological feature of hepatic angiomyolipoma (HAML) that can aid in differential diagnosis, but the pathogenic mechanisms of EVR have yet to be elucidated. We present the first HAML case for which a probable mechanism for EVR is described. The patient was a 46-year-old woman, who had a growing 6-cm tumor with EVR in segment 3 of the liver as revealed by dynamic contrast-enhanced computed tomography. Left hepatic lobectomy was performed to prevent tumor rupture. Histopathological and immunohistochemical analyses of the excised tumor indicated HAML. Successive microsections of the tumor were stained with hematoxylin-eosin and Victoria blue to visualize the vascular structure within and around the tumor. These analyses led to three major findings. First, many well-defined thick-walled vessels, such as arteries, were found entering the tumor. Second, many thick-walled vessels within the tumor were connected directly to thin-walled vessels, resembling arteriovenous fistulae. Finally, thin-walled intratumoral vessels were connected directly to the hepatic vein. These histological findings suggested that the rich arterial flow into the tumor was being rapidly drained into the hepatic vein through intratumoral arteriovenous connections. We also detected these same anomalous circulatory pathways in tissue sections from three of four additional HAML cases with EVR. Aberrant arteriovenous fistulae within the tumor may account for many cases of EVR in HAML patients.

Macrophage-capping protein as a tissue biomarker for prediction of response to gemcitabine treatment and prognosis in cholangiocarcinoma.

Cholangiocarcinoma is one of the deadliest malignancies worldwide. Recent studies reported that treatment with gemcitabine was effective in prolonging survival. However, as the treatment only benefited a limited subset of patients, selection of patients before treatment is required. To discover biomarkers predictive of the response to gemcitabine treatment in cholangiocarcinoma, we examined the proteome of three types of material resource; ten cell lines, nine xenografts and nine surgically resected primary tumors from patients who exhibited different response to gemcitabine treatment. Two-dimensional difference gel electrophoresis generated quantitative protein expression profiles including 3571 protein spots. We detected 172 protein spots with significant correlation with response to gemcitabine treatment. All proteins corresponding to these 172 protein spots were identified by mass spectrometry. We found that the macrophage-capping protein (CapG) was associated with response to gemcitabin treatment in all three types of material source. Immunohistochemical validation in an additional set of 196 cholangiocarcinoma cases revealed that CapG expression was associated with lymphatic invasion status and overall survival. Multivariate analysis showed that CapG protein expression was an independent prognostic factor for overall survival. In conclusion, CapG was identified as a novel candidate biomarker to predict response to gemcitabine treatment and survival in cholangiocarcinoma.