RÉSUMÉ
A man in his 60s, who was diagnosed as having postoperative recurrent gastric cancer with lymph node and spinal metastases, was admitted to our palliative care unit (PCU). He was unable to receive further aggressive chemotherapy for cancer because of bilateral hydronephrosis and chronic renal failure. He had chronic urethral infection and hence required continuous antibiotic administration. Although his infection was well controlled with antibiotics, his oral intake gradually declined. Seventeen days after admission, he developed systemic hemorrhage, including hematuria and oral bleeding. Coagulation tests revealed that the patient had markedly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) but no thrombocytopenia, fibrinogen consumption, or increased fibrin/fibrinogen degradation products (FDP) level. Serum level of protein induced by vitamin K absence or antagonist II (PIVKA-II) was markedly high, and vitamin K level was below the lower limit of the reference range. After he was administered intravenous vitamin K, his symptoms markedly improved. Many patients with advanced cancers tend to have malnutrition, anorexia, and chronic infection that require antibiotic administration. Prophylactic administration of vitamin K might be sometimes necessary for preventing catastrophic hemorrhage.