271 International Journal of HEMATOLOGY Case Report 1. Introduction Sinusoidal obstruction syndrome (SOS), formerly known as venoocclusive disease of the liver, is a specific complica- tion of hematopoietic stem cell transplantation (HSCT) that can lead to substantial morbidity and treatment-related mor- tality. SOS is a clinical syndrome characterized by hyper- bilirubinemia, painful hepatomegaly, and fluid retention [1]. The etiology of this disease is not clearly defined. Drug- induced hepatocellular damage occurs in the centrilobular zones of the liver [2]. The incidence of SOS in allogeneic Sinusoidal Obstruction Syndrome of the Liver after Hematopoietic Stem Cell Transplantation: Decision Making for Orthotopic Liver Transplantation Christian Koenecke, a Moritz Kleine, b Harald Schrem, b Utz Krug, a Bjoern Nashan, c Michael Neipp, b Arnold Ganser, a Bernd Hertenstein, a Juergen Klempnauer b Departments of a Hematology, Hemostasis and Oncology and b Visceral and Transplantation Surgery, Hannover Medical School, Hannover, Germany; c Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada Received September 20, 2005; received in revised form December 7, 2005; accepted December 7, 2005 Abstract Sinusoidal obstruction syndrome (SOS) is a specific complication of hematopoietic stem cell transplantation (HSCT) that can lead to substantial morbidity and treatment-related mortality. Heparin is frequently used as prophylaxis of and defibrotide as therapy for mild to moderate SOS. In severe cases of SOS these therapies are often ineffective, and orthotopic liver trans- plantation (OLT) may be the only option. Reports in the literature about the outcome of liver transplantation for SOS are con- tradictory.We describe our second case of OLT after HSCT.The patient died of intracranial hemorrhage 2 weeks after liver transplantation with good initial organ function. In the first case at our center, however, the patient survived more then 8 years. The reported short- to medium-range survival rate for OLT following HSCT is approximately 50%. On the basis of the expe- rience at our center and the findings in a review of the literature, we developed a rational approach to the selection for liver transplantation of patients with life-threatening liver dysfunction after marrow transplantation. Int J Hematol. 2006;83:271-274. doi: 10.1532/IJH97.E0523 ©2006 The Japanese Society of Hematology Key words: Hematopoietic stem cell transplantation; Orthotopic liver transplantation; Sinusoidal obstruction syndrome Drs. Koenecke and Kleine contributed equally to this work. Correspondence and reprint requests: Christian Koenecke, MD, Department of Hematology, Hemostasis and Oncology, Hannover Medical School, Carl-Neuberg-Str 1, D-30625 Hannover, Germany; 0049-0511-532-2422; fax: 0049-0511-532-8038 (e-mail: koenecke.christian@mh-hannover.de). HSCT is approximately 5.7%; 27.6% of these cases are severe. The mortality is as high as 66.7% [3]. Data indicate that treatment with low-dose heparin dur- ing HSCT may decrease the incidence of SOS [4]. In addi- tion, early treatment with defibrotide is a therapeutic option with a good response in mild and moderate SOS [5]. In the case of severe SOS, however, which usually leads to acute liver failure, liver transplantation may be considered a thera- peutic option. Liver transplantation is an established treatment of fulmi- nant liver failure in specialized centers. Reports about ortho- topic liver transplantation (OLT) in the treatment of some cases of severe SOS had promising results [6,7]. Other cases had a disappointing outcome.Taken together, patients had a high mortality, mainly due to infections or bleeding compli- cations soon after OLT [8-16]. We describe a case of OLT after HSCT and summarize our experience with OLT after severe hepatic SOS after HSCT.We also establish risk stratification for the decision between conservative and surgical treatment of SOS on