We present a case of treatment-refractory adult-onset Rasmussen’s Encephalitis (RE) and successful long-term remission after autologous hematopoietic stem cell transplant (HSCT).  

While hemispherectomy remains the foremost curative treatment in pediatric RE, there are no long-term treatment options for adult-onset RE, which comprises about 10% of cases, and in most situations leads to drug-resistant epilepsy including epilepsia partialis continua (EPC), hemispheric atrophy, and death. AutoHSCT is a previously unexplored treatment option for causes of adult-onset RE. 

A 33-year-old woman presented with progressive aphasia and drug-resistant epilepsy manifested by focal seizures and EPC. Imaging and brain biopsy were consistent with RE involving the left, dominant hemisphere. The disease progressed despite intravenous (IV) steroids, IV immunoglobulin, seven cycles of high-dose cyclophosphamide, and two cycles of rituximab six months apart. Prior to the onset of motor or sensory decline, she underwent autologous HSCT using BEAM (carmustine, etoposide, cytarabine, melphalan) plus anti-thymocyte globulin (ATG) conditioning and CD34-selected autologous stem cells. 

The hospital course was complicated by focal seizures that responded to benzodiazepines. There were no severe infections or high-grade organ toxicity. At six months, she remained free of EPC with normal motor and sensory function and some improvement in baseline aphasia. She had breakthrough EPC in the setting of excessive alcohol intake but without return of inflammatory disease on imaging or requiring additional immunotherapy. She then underwent epilepsy surgery to resect highly epileptogenic tissue, and post-HSCT pathology revealed complete resolution of neuronophagia. At two years post-transplant, the patient’s encephalitis remains in remission.  

Autologous HSCT is a potential successful treatment option for adults with RE or in those who are not candidates for hemispherectomy.