A 38-year-old woman was referred to Seoul National University Boramae Medical Center with dizziness and iron-deficiency anemia (hemoglobin 8.0 g/dL) detected during a medical check-up. Esophagogastroduodenoscopy revealed about 2-cm polypoid mass with a hyperemic surface in antrum along the anterior wall, needing to exclude early gastric carcinoma type I (Fig. 1A). Endoscopic-biopsy mucosal tissue demonstrated a tiny proliferating vascular lesion. Despite oral ferrous sulfate and intravenous iron administration weekly over 15 months, dizziness, fatigue, and anemia were aggravated (hemoglobin 5.4 g/dL). On a follow-up esophagogastroduodenoscopy, the polypoid mass progressed into a gastric ulcer (Fig. 1B). Follow-up biopsy of three times revealed just gastritis or ulceration. Melena once ensued. Proton pump inhibitors (PPIs) or non-steroidal anti-inflammatory drugs (NSAIDs)were never medicated. Stomach computed tomography showed about 1.9-cm intraluminal mass, peripheral enhancement with gradual fill-in/central pitting (Fig. 1C). Inevitably, wedge resection of the stomach was performed (Fig. 2A). Throughout the entire gastric wall, multifocal intravascular/stromal cellular micronodules mingled with vascular components, further, malformed thick-walled blood vessels (Fig. 2B); factor VIII-related antigen/CD31/CD34 (+) in vascular lining endothelium, ETS-related gene (ERG) (+) in both lining and adjacent tumor cells, human herpsevirus 8 (HHV-8) 8 (−), Ki-67 index, 3% immunohistochemically; and wild type isocitrate dehydrogenases (IDH1/2) by Sanger sequencing were observed. She was diagnosed with gastric composite hemangioendothelioma; composed of spindle cell/epithelioid hemangioendothelioma and vascular malformation. No recurrence occurred during the 18-month follow-up after surgical resection.