Recurrent Severe Iron Deficiency Anemia Caused by a Small Bowel Gastrointestinal Stromal Tumor in a 90-Year-Old Woman: A Case Report.

Iron deficiency anemia (IDA) is common in older adults, and gastrointestinal bleeding is an important cause that should be investigated. However, identifying the bleeding source can be challenging when upper and lower gastrointestinal endoscopy findings are negative. We report the case of a 90-year-old woman who presented with anorexia, general fatigue, and dizziness and was found to have severe IDA with a hemoglobin level of 3.9 g/dL. Upper and lower gastrointestinal endoscopy failed to identify the bleeding source. Although her anemia initially improved after blood transfusion and iron supplementation, it recurred, requiring readmission. Double-balloon enteroscopy (DBE) revealed a submucosal tumor with ulceration in the ileum, and surgical resection confirmed an ileal gastrointestinal stromal tumor (GIST). Retrospective review of contrast-enhanced computed tomography (CT) images also identified the corresponding small bowel lesion. This case highlights the importance of considering small bowel lesions in patients with recurrent IDA despite negative findings on upper and lower gastrointestinal endoscopy. It also highlights the value of retrospectively reviewing existing CT images, which may reveal overlooked lesions. Our findings suggest that additional evaluation of the small bowel should be considered in patients with recurrent IDA regardless of advanced age.