An Interesting Paraneoplastic Neurological Manifestation-Case Report

Paraneoplastic limbic encephalitis is an autoimmune disorder, frequently associated with bronchial carcinoma. It is a manifestation of encephalomyelitis, which includes involvement of other regions like pyriform cortex, orbital surface of the temporal lobe, cerebellum and brain stem. 45 yr old male was admitted with complaints of memory disturbance of 2 months with worsening over past 1 month. He also developed neuropsychiatric symptoms such as talking to self, auditory hallucinations,lack of sleep and aggressive behaviour for the past 15 days .He did not have meningeal signs or focal neurological deficit .He was treated for carcinoma lung by full course of chemotherapy one and half years back. We proceeded with CSF examination and MR imaging with contrast. Both serum and CSF samples were sent for analysis of paraneoplastic antibody profiles .CSF analysis was negative for malignant cells,HSV PCR but with presence of moderate pleocytosis. Neuroimaging revealed T2 and FLAIR hyperintensities in bilateral hippocampal regions,not showing much contrast enhancement. Paraneoplastic antibody profile also were negative .With background history of carcinoma lung, we strongly thought of possibility of paraneoplastic limbic encephalitis .We also ruled out other possibilities like CNS infection especially herpes simplex encephalitis and metastases. Eventhough available antibody profiles were negative, diagnosis of paraneoplastic limbic encephalitis is strongly supported by the classical clinical feature , neuroimaging and good response to steroid therapy. This case is presented for its typical clinical and imaging features, and the need to think of the possibility, as this responds well to treatment of primary tumor as well as immunomodulatory therapy.