Malignant epithelioid hemangioendothelioma of the liver - a very rare tumor in children

We report on a 12-year old boy suffering from malignant epithelioid hemangi oendothelioma of the liver,which is a very rare tumor in childhood. The tum or was detected by ultrasound examination at the age of 10 and appeared at that time as a solitary intra hepatic nodular lesion. During the following 2 years multiple nodular lesions developed in both hepatic lobes. There wer e neither any suspect anamnestic findings nor abnormal clinical or laborato ry data. The tumor showed the typical histomorphological, immunohistochemic al,and ultrastructural features of this entity, which is usually seen in ol der patients. We investigated proliferative activity, apoptotic regulation, and expression of VEGF and VEGF-receptor flk-1 by means of immunohistochem ical techniques. According to the known slow growth activity of these tumor s we found only a few Ki-67 positive tumor cells. We did not detect any apo ptotic cells using TUNEL technique. The positive immunoreaction of the tumo r cells with antibodies against VEGF and VEGF-receptor flk-1 may indicate t he regulation of tumor growth by angiogenetic factors. We present our findi ngs together with a summary of the most important publications of recent ye ars concerning these tumors.