Case 1 is a 56-year-old man. During postoperative adjuvant chemotherapy for pancreatic cancer, weakness in the right upper and lower limbs appeared, and a head CT scan was performed, but no abnormal findings were noted. Diffusion- weighted MRI scan of the head showed multiple cerebral infarcts, and a diagnosis of Trousseau syndrome was made. Case 2 is an 86-year-old man. During chemotherapy for postoperative recurrence of distal bile duct carcinoma, he developed weakness in the right upper and lower limbs, and a head MRI scan was performed. Diffusion-weighted MRI showed scattered high-signal areas, and a diagnosis of Trousseau syndrome was made. Trousseau syndrome is a condition in which stroke is caused by hypercoagulability associated with malignant tumor. The initial symptoms of cerebral infarction in patients with cancer are similar to those of chemotherapy-induced adverse events and brain metastases, and therefore, a head MRI scan is recommended even if there is no obvious abnormality on head CT scan.