Multiple gastrointestinal stromal tumors during nilotinib treatment for chronic myelogenous leukemia in a patient with neurofibromatosis type 1

: A 60-year-old woman with neurofibromatosis type 1 presented to our hospital with melena. She reported a 1-year history of treatment with nilotinib hydrochloride hydrate for chronic myelogenous leukemia. Contrast-enhanced abdominal computed tomography revealed multiple intestinal tumors that were subsequently diagnosed as gastrointestinal stromal tumors (GIST) using single-balloon enteroscopy. Although the tumors showed no significant change over 1 year, partial jejunal resection was performed to confirm the diagnosis. Immunohistochemically, the tumors were GIST.