Abstract
Epithelioid hemangioendothelioma (EHE) is a rare vaso-formative tumor of variable biological behavior that has been considered a tumor of borderline malignancy and low-grade angiosarcoma. The majority of cases are associated with low mortality, but some metastasize and cause patient death. Its principal sites of occurrence are soft tissues, liver, lung, and bone. EHE develops as a solitary, painful mass in superficial or deep soft tissue of the extremities and it generally arises from a vessel. Cytogenetic findings are very limited and comprises three reports on totally 4 cases, describing translocations between chromosomes 1 and 3 in two cases, chromosomes 7 and 22 in one case and chromosome 10 and 14 in the last case.
We characterized immunohistochemically 5 cases of this tumour type and currently we are performing Real-Time PCR assays to analyze the expression of two genes (MDM2 and CDK4) known to be involved in pathogenesis of tumours.
Three out 5 patients presented epithelioid hemangioendothelioma of the bone while two affected soft tissues. All the samples showed positivity for CD34 and CD31; 4 samples out 5 were also positive for FLI1. We tested Factor VIII immunostaining on 3 of these cases which resulted positive; EMA was positive on 3 samples out 5. Cytocheratins (AE1/AE3, CAM 5.2 and CK7) were always negative except in one case which showed CAM 5.2 positivity. Our preliminary results by Real-Time PCR analysis performed on 5 cases suggest that MDM2 and CDK4 have a different expression in epithelioid hemangioendotheliomas compared to normal tissue.
Our study shows that use of molecular techniques such as Real-Time PCR could complement histopathological diagnosis in order to identify a marker of biologic behaviour of this enigmatic tumour type.
Correspondence should be addressed to Professor Stefan Bielack, Olgahospital, Klinikum Stuttgart, Bismarkstrasse 8, D-70176 Stuttgart, Germany. Email: s.bielack@klinikum_stuttgart.de
