Epithelioid hemangioendothelioma (EHE) is a rare vascular sarcoma with a prevalence of approximately 1 per 1 000 000 persons.1 A hallmark molecular characteristic of EHE is the fusion of the WWTR1 and CAMTA1 genes, present in 90% of EHE cases and pathognomonic for disease.2,3,4 The clinical course of EHE may be either indolent (often locally limited) or aggressive (characterized by local invasiveness or metastasis); however, indolent disease can unpredictably become aggressive. The gene discussed is WWTR1; the disease is epithelioid hemangioendothelioma.