Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

Lambert-Eaton myasthenic syndrome associated with pulmonary squamous cell carcinoma and circulating anti-P/Q-type voltage-gated calcium channel antibody

Eiichi Katada, M.D.1), Tomohiko Nakamura, M.D.2), Hirohisa Watanabe, M.D.2), Noriyuki Matsukawa, M.D.3), Kosei Ojika, M.D.3) and Gen Sobue, M.D.2)

1)Department of Neurology, Nagoya City West Medical Center Johoku Municipal Hospital
2)Department of Neurology, Nagoya University Graduate School of Medicine
3)Department of Neurology and Neuroscience, Nagoya City University Graduate School of Medical Science

We report a 64-year-old man diagnosed with Lambert-Eaton myasthenic syndrome (LEMS) associated with pulmonary squamous cell carcinoma. Circulating anti-P/Q-type voltage-gated calcium channel (VGCC) antibody was detected, and the patient was treated with 3,4-diaminopyridine. At age 61, chest radiograph revealed a tumor shadow in the right upper lung field. This was surgically removed, and a histological diagnosis of moderately differentiated pulmonary squamous cell carcinoma was obtained. After about 1 year, mediastinal metastasis was detected and 5-FU was administered. Eight months later, metastasis was noted in the left frontal hemisphere, and radiosurgical therapy was performed. The brain tumor gradually shrank, but generalized fatigue, thirst, and gait disturbance developed after 4 months. A diagnosis of LEMS was made on the basis of neurological findings including proximal muscle weakness and absent tendon reflexes; autonomic symptoms (thirst, constipation, and impotence); characteristic electromyographic findings; and circulating anti-P/Q-type VGCC antibody. He has been treated with 3,4-diaminopyridine at a dose of 30 mg/day, resulting in marked improvement in symptoms but little change in electromyographic findings. The present case is very rare and suggests that anti-P/Q-type VGCC antibody may be involved in the mechanism of LEMS associated with pulmonary squamous cell carcinoma.
Full Text of this Article in Japanese PDF (471K)

(CLINICA NEUROL, 50: 17|19, 2010)
key words: Lambert-Eaton myasthenic syndrome, lung cancer, pulmonary squamous cell carcinoma, anti-P/Q-type voltage-gated calcium channel antibody, 3,4-diaminopyridine

(Received: 5-Dec-08)