Epithelioid hemangioendothelioma: a study of 14 cytopathology cases

The cytopathologic diagnosis of the rare vascular tumor epithelioid hemangioendothelioma (EHE) in patients who have no previous history of EHE or who have a complicated and/or misleading disease history is challenging. Furthermore, few studies have described the cytopathology of EHE. Herein, we identify 14 cases of EHE from 10 patients, some of whom had a history of epithelial tumor, and provide a detailed report of the cytomorphology of EHE, discuss the tumor's differential diagnoses, and describe ancillary examinations that may be helpful in diagnosing EHE cytologically, especially in patients with a complex disease history.

We retrieved the slides of 14 cases of EHE archived between 2002 and 2009 in our institution's cytology section. Conventional direct smears and cell block sections were prepared from most fine-needle aspiration samples and from all effusion samples. Cell block sections were subjected to immunostaining for vascular, mesothelial, and epithelial markers.

EHE shared many morphologic features with other, more common tumors such as adenocarcinoma and mesothelioma. The defining cytologic feature of EHE was an intracellular lumen containing entrapped intact and degenerating erythrocytes, which was not present in every case. EHE cells were positive for the vascular markers CD34, CD31, factor VIII, and friend leukemia integration 1 transcription factor (FLI-1) and negative for epithelial and mesothelial markers. Clinicians provided information important to the diagnosis of EHE.

Carefully examining the smear and cell block sections for morphologic features indicative of EHE (eg, prominent cytoplasmic vacuolization, intranuclear cytoplasmic inclusions, and intracellular lumen containing entrapped intact and degenerating erythrocytes), confirming these findings with immunocytochemical staining, and communicating with clinicians are all important to correctly diagnosing EHE.