A 23-year-old woman who complained of abdominal distension and
anorexia was referred to our hospital. Computed tomography showed
ascites, a huge hepatic
tumor and ovarian
tumor. Gastroscopy revealed type 4
gastric cancer and biopsy examination showed poorly differentiated
adenocarcinoma with
signet ring cell carcinoma. We diagnosed her with stage IV advanced gastric
adenocarcinoma. She received the
chemotherapy with S-1 and CDDP regimen. After two courses, this regimen was changed to the SOX (S-1 + OHP) regimen because of
acute kidney injury. After one course of the SOX regimen, she developed general
muscle cramp. Magnetic resonance imaging showed a 15 mm, round, high-intensity signal at the parietal lobe on T2-weighted images. She was hospitalized for with the suspicion of brain
metastasis.
Anticonvulsants improved her
muscle cramp, but she had consciousness disturbance on the 9th hospital day. T2WI showed high-intensity signals within the cerebral white matter at both sides of the occipital lobe. We suspected
leukoencephalopathy caused by S-1 and discontinued the SOX regimen. We also treated her
hypertension and
hyponatremia. Her consciousness disturbance improved in several days, and the T2WI finding was markedly improved on the 20th hospital day. We diagnosed her with
posterior reversible encephalopathy syndrome caused by
chemotherapy containing S-1.