WWTR1, also known as TAZ (Transcriptional coactivator with PDZ binding motif), is a transcriptional coactivator that regulates expression of genes involved in cell proliferation and differentiation. YAP1 and TAZ (WWTR1) oncoproteins are the final transducers of Hippo tumor suppressor pathway. Deregulation of the pathway leads to YAP1/TAZ activation fostering tumorigenesis in multiple malignant tumor types, including sarcoma. Epithelioid hemangioendothelioma (EHE) is a rare vascular sarcoma characterized by the WWTR1-CAMTA1 fusion (WC-F) in a majority of cases. Epithelioid hemangioendotheliomas (EHEs) are rare vascular tumors composed of neoplastic endothelial cells with features of chain or cord-like structure or intracytoplasmic lumen in a myxohyaline matrix. While 90% of classic EHE are driven by a WWTR1-CAMTA1 fusion gene, a histologically distinctive subset of EHE has been recently shown to harbor a different fusion gene, YAP1-TFE3.