[A case of small cell lung cancer that presented with paraneoplastic syndrome].
ABSTRACT A 65-year-old man had suffered from systemic erythema from November 2008 and had noticed gradually progressing weakness in the upper and lower limbs. He received medical treatment in another hospital but his symptoms did not improve. He was admitted to our hospital for treatment of diabetes in June 2009, and his chest X-ray images and CT scans showed a mass shadow in the right upper lobe with hilar and mediastinal lymphadenopathy. We performed bronchoscopy, and diagnosed small cell lung cancer (T2N2M1, stage IV). However, he had hand grip weakness and continuing upper and lower limb muscle weakness, and therefore electromyography was performed, which showed the presence of waxing in the right leg. Subsequently, a diagnosis of Lambert-Eaton myasthenic syndrome was made. As he also showed ataxia of the left lower extremity, we also diagnosed paraneoplastic cerebellar degeneration. We gave the patient chemotherapy consisting of carboplatin and etoposide which resulted in the disappearance of his waxing, and his grip strength and erythema immediately improved with regression of the tumor after 1 course of chemotherapy. We report a case of small cell lung cancer associated with Lambert-Eaton myasthenic syndrome, paraneoplastic cerebellar degeneration and erythema which presented as paraneoplastic syndrome, which improved with chemotherapy.