Iron Deficiency Anemia Unmasking an Endoscopically Resectable GIST

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that most commonly arise in the stomach and typically present with overt upper gastrointestinal bleeding, abdominal pain, or are discovered incidentally. Iron-deficiency anemia as an initial manifestation, especially in the context of a small gastric lesion, is infrequently reported. We present the case of a 59-year-old male who presented with one day of melena and newly identified microcytic anemia without hemodynamic instability. Laboratory tests confirmed iron-deficiency anemia, prompting cross-sectional imaging that revealed a 3.8 × 3.5 cm submucosal antral mass. Endoscopy demonstrated a smooth subepithelial bulge near the pylorus, and endoscopic ultrasound with fine-needle biopsy identified an epithelioid-type GIST. The patient underwent complete endoscopic enucleation of the tumor with negative margins. Postoperative recovery was uneventful, and surveillance imaging at twelve months confirmed the absence of recurrence. This case is notable for the unusual presentation of a small gastric GIST with iron-deficiency anemia, the less common epithelioid morphology, and the successful use of minimally invasive endoscopic management. It underscores the need to consider subepithelial gastric tumors in patients presenting with unexplained anemia, even in the absence of significant gastrointestinal symptoms. Early recognition and multidisciplinary evaluation remain essential for prompt diagnosis, appropriate risk stratification, and optimal therapeutic planning in localized GISTs.