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Introduction
Limbic encephalitis is a rare neurological syndrome that selectively affects the structures of the limbic system, including the hippocampus, amygdala and hypothalamus. Since the initial cases of this disease were often accompanied by cancer, such as small cell lung cancer (SCLC), the disease was subsequently referred to as paraneoplastic limbic encephalitis (PLE) (1–6). The main clinical manifestations of PLE are seizures associated with progressive short-term memory loss, which may develop into dementia. In addition, there may be different degrees of involvement in such extra-limbic-system tissues as the cerebellum, brainstem and thalamus. Electroencephalography (EEG) typically exhibits epileptic activity in the unilateral or bilateral temporal lobes, with focal or global slow waves; magnetic resonance imaging (MRI) T2 or flair images show high-signal, abnormal lesions in the interior sides of the unilateral or bilateral temporal lobes. In the majority of cases, temporal lobe atrophy develops. Cerebrospinal fluid examination typically exhibits inflammatory changes, with mildly to moderately increased lymphocytes, as well as increased protein levels; glucose levels would be normal and the immunoglobulin G (IgG) index would most likely be increased. Furthermore, oligoclonal bands would be apparent (7–9).
A number of studies have revealed that the pathogenesis of PLE is an immune-mediated response, primarily effected by cytotoxic T cells and antibodies that act on neuronal antigens, such as anti-Hu (10,11), anti-Ma2 (12), anti-amphiphysin (13) and anti-Yo (14) antibodies. Treatments for PLE include anti-cancer therapy and immunotherapy; the effects of the former are more marked, but the overall prognosis is typically poor (8,15). Research into PLE has made progress over the past decade (16), and certain clinical manifestations and imaging appearances have been found to be consistent with PLE. Furthermore, since the generation of antibodies targets neuronal cell membrane antigens, the development of specific immunotherapies could lead to improvements in prognosis for patients with PLE (15,17). To date, few studies have focused on PLE in patients of Chinese Han nationality; therefore, the present study described two cases of PLE in patients of Chinese Han nationality and summarized four cases in the literature.
Materials and methods
Clinical data
Two male patients with PLE associated with SCLC were hospitalized in the Department of Neurology, the First Affiliated Hospital of Bengbu Medical College (Bengbu, China) between October 1999 and July 2013....