Yoko Kosaka, Hiromichi Yamane, Hidekazu Nakanishi, Nagio Takigawa
ABSTRACT A 76‐year‐old man was referred to our hospital for evaluation of anemia. Although he was elderly (≥75 years), no apparent risk factors for bleeding during endoscopic biopsy, such as renal dysfunction or anticoagulant therapy, were identified. Upper gastrointestinal endoscopy revealed extensive atrophic gastric mucosa extending from the antrum to the gastric body. A biopsy was obtained from the atrophic mucosa in the antrum for histopathological evaluation after confirming a low risk of bleeding. Eight days after the initial endoscopy, the patient was hospitalized and started on nilotinib for chronic myeloid leukemia, which had been subsequently diagnosed. Gastrointestinal bleeding occurred 5 h after the initiation of nilotinib. Emergency endoscopy revealed a reddish polypoid lesion with active bleeding at the previous biopsy site. Endoscopic polypectomy was performed, and hemostasis was achieved. Delayed gastric bleeding after upper gastrointestinal endoscopic biopsy alone is extremely rare. Current guidelines in Japan state that tissue biopsy is acceptable when clinically indicated, even in patients receiving anticoagulant or antiplatelet therapy. Although no definitive cause was identified, myeloproliferative disorders are associated with bleeding tendencies due to coagulation abnormalities and drug‐induced bleeding related to tyrosine kinase inhibitors such as dasatinib and nilotinib. These factors may have contributed to the delayed bleeding in this case. This case highlights the importance of careful follow‐up after endoscopic biopsy in patients with underlying myeloproliferative disorders. Trial Registration : N/A.