A Patient with Small Cell Lung Cancer Presenting with Symptoms of Lambert-Eaton Myasthenic Syndrome Case Report
Abstract:
Background: Small cell lung cancer (SCLC) accounts for about 10-15% of lung cancer. Early diagnosis and treatment of lung cancer can effectively improve the quality of life. From the literature, it is known that Lambert-Eaton Myasthenic Syndrome (LEMS) is a paraneoplastic syndrome, and its symptoms may precede those of cancer. In this case, the patient was first diagnosed with LEMS and later found to have SCLC. Following appropriate treatment, the patient's muscle strength improved.
Case Description: A 60-year-old man with neck weakness, exertional dyspnea, proximal muscle weakness, and weight decreased from 80 kg to 60 kg in two months. First suspected diagnose was MG, patient received neurological examination (Electromyography, repetitive stimulation tests), the blood tests of anti-acetylcholine receptor antibodies (anti-AChR Ab) and anti-muscle-specific kinase antibodies (anti-MuSK Ab) were negative. LEMS was highly suspected. LEMS was frequently found with Small Cell lung cancer patients; our chest CT revealed mediastinal and right hilar lymphadenopathy, after the biopsy pathology report showed metastatic neuroendocrine carcinoma, consistent with SCLC. When Diagnosis confirmed, we started the chemotherapy. The patient’s muscle strength improved to 5.
Conclusions: Electromyography and repetitive stimulation tests should be conducted early. While anti-voltage-gated calcium channel (anti-VGCC) antibodies test have a 90% specificity. LEMS was highly assosiated with SCLC. Tumor treatment can significantly affect the symptoms of myasthenia to have a better quality of life.
