[Successful treatment of very severe late-onset sinusoidal obstruction syndrome with recombinant human soluble thrombomodulin, steroids, and control of intra-abdominal pressure].

We report a case of a 16-year-old woman who achieved her third complete remission of acute lymphoblastic leukemia after undergoing allogeneic stem cell transplantation for the second time from an unrelated donor. On post-transplantation day 30, she showed weight gain, hepatomegaly, right hypochondriac pain, and ascites. On day 35, ultrasonography (US) revealed portal vein regurgitation. She was subsequently diagnosed with late-onset sinusoidal obstruction syndrome (SOS) and was transferred to the intensive care unit (ICU) on day 36 for multiple organ dysfunction syndrome (MODS) and disseminated intravascular coagulation, requiring mechanical ventilation. Her SOS was graded as very severe upon ICU admission. Recombinant human soluble thrombomodulin (380 U/kg/day) and methylprednisolone (2 mg/kg/day) therapies were initiated. Additionally, her intra-abdominal pressure had increased to 19 mmHg, which was thought to be the cause of MODS. Ascites drainage (1,000 ml/day), according to the treatment for abdominal compartment syndrome, improved her SOS and MODS. She was weaned from mechanical ventilation on the 10th day after ICU transfer, and US showed resolution of the portal vein regurgitation. She was transferred to the general ward on the 14th day. She had not experienced disease recurrence at her last visit (527 days after the second transplantation).