Epithelioid hemangioendothelioma (EHE) of the lung is a low-grade malignant tumor of vascular origin initially described under the name intravascular bronchioloalveolar tumor (IVBAT). We present a case of a 44-yr-old Caucasian female with severe radiating back pain, shortness of breath, recurrent malignant pleural effusions, and a negative malignancy workup. Cytopathologic examination of the four pleural fluid specimens revealed large undifferentiated plasmacytoid malignant cells with abundant pink and finely granular cytoplasm, round nuclei, and prominent nucleoli. The differential diagnosis based on the cytologic findings included hepatocellular, adrenal, and renal carcinomas, melanoma, mesothelioma, and neuroendocrine tumors. Electron microscopy performed on a pleural fluid specimen and subsequent histologic examination of pleural and lung biopsies established the diagnosis of EHE.