Cytologic features, immunocytochemical findings, and DNA ploidy in four rare cases of epithelioid hemangioendothelioma involving effusions

Background: Epithelioid hemangioendothelioma (EHE) involving serous effusion is extremely rare, and the diagnosis can be challenging. DNA ploidy quantitation of EHE in effusion fluids has not been previously described in the English-language literature. Methods: Specimens of cytological diagnosed with EHE in effusion fluids between 2002 and 2009 were retrieved from the pathology files at MD Anderson Cancer Center. A total of four cases of EHE involving or arising from effusion fluids were found, and we reviewed cytospin, smears, cell block sections, and immunostained slides. DNA image analysis for ploidy and proliferation evaluation was performed on a destained, papanicolaou-stained slide from each case. Results: The tumor cells were epithelioid with prominent cytoplasmic vacuolization and intracytoplasmic inclusions, which could resemble reactive mesothelial cells, mesothelioma, or adenocarcinoma. The tumor cells were positive for endothelial markers. DNA image analysis in three of the four cases revealed predominantly diploid and tetraploid subpopulations, with few aneuploid cells and fairly low proliferation indices, and these patients had fairly prolonged survival. Conclusions: DNA image analysis is useful for differentiating EHE from reactive mesothelial cells and high-grade carcinoma. For accurate diagnosis of EHE in effusion fluids, cytologic features should be considered together with clinical history and ancillary studies.