ALK and carcinoma of duodenum: While studies on genotype-directed therapy in patients with duodenal carcinoma is progressing, clinical data assessing the efficacy of molecularly targeted therapy remains scarce. We report the case of a 65-year-old woman diagnosed with anaplastic lymphocyte kinase (ALK) fusion-positive advanced duodenal carcinoma. The patient had been treated with alectinib for approximately 2 years for ALK-positive duodenal carcinoma but developed progressive liver metastases, indicating alectinib failure.