A 40-year-old female was referred to our hospital for further examination of gastric ulcers. Upper gastrointestinal endoscopy revealed ulcer scars and a pyloric hematoma that developed due to stimulation by the endoscope. Lower gastrointestinal endoscopy revealed multiple submucosal hematomas in the sigmoid colon. Biopsy specimens were obtained from the stomach, duodenum and colon. Histological examination revealed amyloid protein deposition, and Bence-Jones protein was detected in the urine. The patient was diagnosed with AL amyloidosis caused by multiple myeloma and received chemotherapy. It is important to be able to recognize the typical endoscopic findings of AL amyloidosis such as submucosal hematomas and identify amyloid protein deposition in endoscopic biopsy specimens to diagnose amyloidosis of the gastrointestinal tract. Therefore, the physician should report the probability of gastrointestinal amyloidosis to the pathology department so that they can perform a detailed examination.
