Paraneoplastic limbic encephalitis as a cause of new onset of seizures in a patient with non-small cell lung carcinoma: a case report

INTRODUCTION: The etiology of seizure disorders in lung cancer patients is broad and includes some rather rare causes of seizures which can sometimes be overlooked by physicians. Paraneoplastic limbic encephalitis is a rather rare cause of seizures in lung cancer patients and should be considered in the differential diagnosis of seizure disorders in this population. CASE PRESENTATION: This case report describes the new onset of seizures in a 64-year-old male patient receiving chemotherapy for a diagnosed stage IV non-small cell lung carcinoma. After three cycles of therapy, he was re-evaluated with a chest computed tomography which showed a 50% reduction in the tumor mass and in the size of the hilar and mediastinal lymphadenopathy. Twenty days after the fourth cycle of chemotherapy, the patient was admitted to a neurological clinic because of the onset of self-limiting complex partial seizures, with motionless stare and facial twitching, but with no signs of secondary generalization. The patient had also recently developed neurological symptoms of short-term memory loss and temporary confusion, and behavioral changes. Laboratory evaluation included brain magnetic resonance imaging, magnetic resonance spectroscopy of the brain, serum examination for 'anti-Hu' antibodies and stereotactic brain biopsy. Based on the clinical picture, the patient's history of lung cancer, the brain magnetic resonance imaging findings and the results of the brain biopsy, we concluded that our patient had a 'definite' diagnosis of paraneoplastic limbic encephalitis and he was subsequently treated with a combination of chemotherapy and oral steroids, resulting in stabilization of his neurological status. Despite the neurological stabilization, a chest computed tomography which was performed after the 6th cycle showed relapse of the disease in the chest. CONCLUSION: Paraneoplastic limbic encephalitis is a rather rare cause of new onset of seizures in patients with non-small cell lung carcinoma. Incidence, clinical presentation, laboratory evaluation, differential diagnosis, prognosis and treatment of this entity are discussed.