Case Report Left Vocal Cord Paralysis Detected by PET/CT in a Case of Lung Cancer Ali Ozan Oner, 1 Adil Boz, 2 Evrim Surer Budak, 3 and Gulnihal Hale Kaplan Kurt 4 1 Nuclear Medicine Department, School of Medicine, Afyon Kocatepe University, 03200 Afyon, Turkey 2 Nuclear Medicine Department, School of Medicine, Akdeniz University, 07070 Antalya, Turkey 3 Nuclear Medicine Department, Antalya Training and Research Hospital, Antalya, Turkey 4 Nuclear Medicine Department, Isparta State Hospital, Isparta, Turkey Correspondence should be addressed to Adil Boz; boz@akdeniz.edu.tr Received 6 September 2015; Accepted 18 October 2015 Academic Editor: Jose I. Mayordomo Copyright © 2015 Ali Ozan Oner et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We report a patient with lung cancer. Te frst PET/CT imaging revealed hypermetabolic mass in the lef aortopulmonary region and hypermetabolic nodule in the anterior segment of the upper lobe of the lef lung. Afer completing chemotherapy and radiotherapy against the primary mass in the lef lung, the patient underwent a second PET/CT examination for evaluation of treatment response. Tis test demonstrated, compared with the frst PET/CT, an increase in the size and metabolic activity of the primary mass in the lef lung in addition to multiple, pathologic-sized, hypermetabolic metastatic lymph nodes as well as multiple metastatic sclerotic areas in bones. Tese fndings were interpreted as progressive disease. In addition, an asymmetrical FDG uptake was noticed at the level of right vocal cord. During follow-up, a laryngoscopy was performed, which demonstrated lef vocal cord paralysis with no apparent mass. Tus, we attributed the paralytic appearance of the lef vocal cord to infltration of the lef recurrent laryngeal nerve by the primary mass located in the apical region of the lef lung. In conclusion, the knowledge of this pitfall is important to avoid false-positive PET results. 1. Introduction Vocal cord paralysis occurs due to pathologies of the nerves that innervate vocal cords. Te nerves that make vocal cords vibrate consist of neurons originating from the region of nucleus ambiguus in the brainstem. Te nerve arising from the nucleus is called the “vagus nerve,” which is the thickest nerve in the human body and extends to thoracic and abdominal cavities [1]. Te nerve gives of 2 thin branches for larynx at the base of the skull. Te frst one is called the “superior laryngeal nerve” and the second one is called the “recurrent laryngeal nerve (RLN).” Te latter conveys orders to both opening and closure muscles. Te problems in that nerve cause paralysis of both opening and closure muscles, leading to loss of their basic functions. Hence, respiratory difculty and hoarseness and aspiration problems due to failure of closure arise. Problems of superior laryngeal nerve, on the other hand, become manifest, with a monotonous, thin voice as well as difculty in tone control and singing songs. Causes of Vocal Cord Paralysis: (i) Idiopathic diseases. (ii) Viral neuritis. (iii) Masses, tumors compressing vocal nerves in brain, base of the skull, neck, thyroid region, and thoracic cavity. (iv) Surgical interventions (especially thyroid surgery). (v) Being secondary to intubation in certain surgical operations [1]. 18 F-fuorodeoxyglucose positron emission tomography/ computed tomography ( 18 FDG-PET/CT) scans are utilized for identifcation of stage cancers clinically but the causes of false-positive and false-negative results must be identi- fed to evaluate the results of the test. As a result of the increased glucose consumption, FDG accumulates in benign and malignant conditions. Te degree of muscle work is Hindawi Publishing Corporation Case Reports in Oncological Medicine Volume 2015, Article ID 617294, 4 pages http://dx.doi.org/10.1155/2015/617294