Sporadic Fatal Insomnia Masquerading as a Paraneoplastic Cerebellar Syndrome

Abstract

Sporadic fatal insomnia is a rare prion disease that has recently been recognized. To report a unique case of sporadic fatal insomnia in a woman with progressive cerebellar deterioration who was originally thought to have a paraneoplastic cerebellar syndrome. Case report describing a patient with autopsy-proven sporadic fatal insomnia. A 56-year-old woman with progressive cerebellar ataxia who was found to have a retroperitoneal non-Hodgkin lymphoma. Autopsy demonstrated marked degenerative changes in the thalamus, cerebellum, and inferior olivary nucleus. A mild spongiform change was present in the thalamus and cortical gray matter. Western blot analysis confirmed the presence of abnormal, protease-resistant prion protein (PrP(Sc)), characteristic of sporadic fatal insomnia. Clinicians should be aware of this rare prion disease and should strongly consider the importance of autopsy toward the investigation of unusual neurological diseases.