Biopsy Proven Late-Onset Sinusoidal Obstruction Syndrome Successfully Treated With Defibrotide

We report an unusual case of a patient who developed a biopsyproven Sinusoidal Obstruction Syndrome (SOS) more than 4 months after a nonmyeloablative allogeneic sibling transplant. The patient responded to defibrotide treatment with clear improvement in liver function and normalization of radiologic findings. Although a few cases of late-onset SOS have been reported in the literature, we describe, to the best of our knowledge, the first case of late-onset SOS successfully treated with defibrotide after allogeneic hematopoietic stem cell transplantation.