Spongiform encephalopathy following allogeneic cord blood transplant.

A 6 year old boy developed a fatal, rapidly progressive encephalopathy 5 months after a matched unrelated cord blood transplant. Autopsy findings revealed spongiform changes in his brain. The clinical course of this child's illness had many findings consistent with that of a transmissible spongiform encephalopathy (TSE). Pre-mortem and post-mortem studies failed to definitively determine an etiology. Spongiform encephalopathies include the TSEs and mitochondrial encephalopathies. Both should be considered in a post-hematopoietic stem cell transplant patient who develops a progressive encephalopathy when more common etiologies are not found.