Paraneoplastic Encephalomyelitis, Paraneoplastic Encephalitis


a.k.a. paraneoplastic encephalitis, a.k.a. paraneoplastic limbic encephalits


A combination of serology,  clinical features and identification of underlying tumor

Clinical features:

Subacute impairment, seizures, temporal lobe seizures & hallucinations,
Other features may occur:,


Limbic encephalitis (medial temporal lobe, hippocampus, amygdala, cingulate gyrus, inula), thalamus, brainstem encephalitis, cerebellum, spinal cord grey matter, dorsal root ganglia (sensory neuropathy), peripheral nerves, myenteric plexus.
Gross: bilateral necrosis.

  • CNS: Massive neuronal loss, neuronophagea. Astrocytic gliosis, rod-shaped microglia. Perivascular & intraparenchymal lymphocytic infiltrates.
  • Ganglia: loss of ganglion cells. Prominent inflammatory infiltrates.
  • Peripheral nerves: axonal degeneration with secondary demyelination. Mild perivascular & parenchymal mononclear infltrates.

Findings on Investigations:

MRI: usually bilateral involvement of temporal lobes. Atrophy of the temporal lobe is common. Brainstem or hypothalamic involvement may occur. Hemorrhage is rare. T2 hyperintense, FLAIR hyperintense.

  • Limbic encephalitis  autoantibodies:
    • Some of these autoantibodies are more strongly associated with neoplasm that others
    • Anti-: Hu (ANNA-1), amphiphysin, CV2/CRMP5, LGI1, CASPR2, VGKC, NMDA (NR1), GAD65, MaTa,
  • Voltage-gated potassium channels VGKC, usually not paraneoplastic
  • Anti-NMDA receptor antibodies: ovarian teratoma. Associated with orolingual dyskinesias & catatonia like state.


Treat the underlying tumor
Consider IVIg, plasma exchange,

Related articles: