Incapacitating lower limb pain syndrome in cord blood stem cell transplant recipients with calcineurin inhibitor

Calcineurin-inhibitor induced pain syndrome (CIPS) is a newly described entity with a characteristic feature of sudden onset of severe lower limb pain, and high levels of cyclosporine or tacrolimus may be involved in the pathogenesis. This syndrome is rarely seen in recipients of hematopoietic stem cell transplantation (HSCT) compared with other organ transplant recipients, however, heightened awareness of this complication after HSCT may be needed for hematologists, as misdiagnosis can result in catastrophic consequences. We report herein two cases of lower limb pain syndrome, with some clinical features resembling CIPS, occurring during the early phase of cord blood stem cell transplantation for hematological malignancy.