Multiple Myeloma Presenting as Lower Gastrointestinal Bleeding: A Case Report

Multiple myeloma (MM) is a malignant hematologic neoplasm that primarily affects the bone marrow and can invade other organs, leading to diverse clinical manifestations. Presentation with gastrointestinal bleeding as the initial symptom is exceptionally rare. We report a case of MM in a 46-year-old man who presented with gastrointestinal bleeding and severe anemia. Routine endoscopic evaluation was inconclusive, but further hematologic and imaging investigations confirmed multiple myeloma. The patient was successfully treated with bortezomib-based chemotherapy and supportive care. This case emphasizes the importance of considering plasma cell dyscrasias in patients with unexplained GI bleeding and anemia, particularly when conventional gastrointestinal causes are excluded.