Neuroimaging in status epilepticus secondary to paraneoplastic autoimmune encephalitis.
OBJECTIVE
To describe the characteristic magnetic resonance imaging (MRI) findings of paraneoplastic autoimmune encephalitis in patients with new-onset status epilepticus.


METHODS
The neuroimaging and clinical data of five patients with paraneoplastic autoimmune encephalitis debuting as status epilepticus were retrospectively reviewed. All patients met the criteria for definite paraneoplastic syndrome and all underwent brain MRI during the status epilepticus episode or immediately after recovery.


RESULTS
All patients showed hyperintense lesions on T2-weighted imaging (WI) involving the limbic structures, specifically the hippocampus. Three of them showed additional extra-limbic areas of signal abnormalities. The areas of T2 hyperintensity were related to the electroclinical onset of the seizures. In three patients, various techniques were used to study cerebral perfusion, such as arterial spin labelling MRI, single photon-emission computed tomography (SPECT) and 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG)-positron-emission tomography (PET). Arterial spin labelling showed hyperperfusion overlapping the inflammatory lesions, whereas PET and SPECT disclosed increased perfusion and increased metabolism. The subtraction SPECT co-registered to MRI (SISCOM) demonstrated hypermetabolism outside the areas of encephalitis. After clinical recovery, follow-up MRI revealed the development of atrophy in the initially affected hippocampus. Two patients who had recurrent paraneoplastic autoimmune encephalitis manifesting as status epilepticus showed new T2 lesions involving different structures.


CONCLUSIONS
The presence of limbic and extra-limbic T2 signal abnormalities in new-onset status epilepticus should suggest the diagnosis of a paraneoplastic syndrome, especially when status epilepticus is refractory to treatment. The lesions are consistently seen as hyperintense on T2WI.
Magnetic Resonance Unit, Radiology Department, Vall d'Hebrón University Hospital, Barcelona, Spain. Electronic address: ssarria@idi-cat.org.
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Sarria-Estrada
Epilepsy Unit, Neurology Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
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Toledo
Nuclear Medicine Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
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Lorenzo-Bosquet
Nuclear Medicine Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
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Cuberas-Borrós
Magnetic Resonance Unit, Radiology Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
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Auger
Magnetic Resonance Unit, Radiology Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
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Siurana
Magnetic Resonance Unit, Radiology Department, Vall d'Hebrón University Hospital, Barcelona, Spain.
A
A
Rovira
D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001927:Brain Diseases / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D001931:Brain Mapping / Q000379:methods*; D004660:Encephalitis; D005260:Female; D019788:Fluorodeoxyglucose F18; D050031:Hashimoto Disease / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods*; D020361:Paraneoplastic Syndromes, Nervous System / Q000150:complications / Q000175:diagnosis*; D049268:Positron-Emission Tomography / Q000379:methods; D011859:Radiography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013226:Status Epilepticus / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18