Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 10 2013 10 15 724 726 EN Masoud Mehrpour Department of Neurology, Firoozgar General Hospital, Tehran University of Medical Sciences, Tehran, Iran. Nafiseh Mohebi Department of Neurology, Firoozgar General Hospital, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Reza Motamed Department of Neurology, Firoozgar General Hospital, Tehran University of Medical Sciences, Tehran, Iran. Farhad Zamani Gastrointestinal and Liver Diseases Research Center, Firoozgar General Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 11 Motor neuron diseases have been reported as a rare paraneoplastic syndrome (PNS) of a systemic neoplasm. We present a patient with amyotrophic lateral sclerosis (ALS) in association with neuroendocrine tumor (NET) of stomach, which is the first case of motor neuronopathy with underlying neuroendocrine tumor. A 79-year old woman presented with a two months history of progressive dysphagia, spastic dysarthria and marked fasciculation in her atrophic tongue. Gag reflexes were diminished bilaterally. Other cranial nerves were intact. In muscle testing there was significant atrophy in thenar and hypothenar areas of both hands compatible with diffuse motor neuronopathy with active denervation. Upper GI endoscopic study showed patchy erythematous mucosa with congestion in body of stomach, Histological biopsy of stomach confirmed the neuroendocrine tumor (NET). The importance of considering a paraneoplastic syndrome in a patient with presentation of ALS, which can leads to searching for underlying neoplasm before its apparent signs and symptoms, to initiate tumor treatment so much sooner. In addition even though paraneoplastic motor neuron disease is rare, treating the underlying neoplasm may resolve neurologic signs and symptoms. https://acta.tums.ac.ir/index.php/acta/article/view/4374 https://acta.tums.ac.ir/index.php/acta/article/download/4374/4430