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Letters Tracheal Paraganglioma: Differential Diagnosis of a Contrast-Enhanced Tracheal Mass We read with great interest the case reported by Ngo et al. [1], who described an approach to large airway lesions and discussed the imaging characteristics and clinical presentations. We would like to report our experience with a rare case involving an important differential diagnosis of a contrast-enhanced tracheal mass. A 35-year-old man with a history of bronchial asthma was admitted with cough, hoarseness, and shortness of breath over the previous 4 days. Physical examination showed respiratory distress with mild expiratory stridor in the cervical trachea. Unenhanced CT (Figs. 1A and 1B) revealed a mass in the posterior wall of the cervical trachea. Contrast-enhanced CT (Figs. 1C and 1D) showed a contrast-enhanced mass with a necrotic center. Bronchoscopy showed the presence of a tumor on the posterior trachea. The patient underwent uneventful surgical resection and recovered well. The histopathologic diagnosis was paraganglioma. Ninety percent of tumors originating in chromaffin cells are pheochromocytomas, which are located in the adrenal gland. The remaining 10% are extraadrenal tumors, termed “paragangliomas.” Paragangliomas appear in the abdomen, pelvis, neck, and

mediastinum. Mediastinal paragangliomas originate from paraaortic (middle mediastinum) and paravertebral (posterior mediastinum) sympathetic chain ganglia [2–4]. Like pheochromocytomas, paragangliomas may secrete catecholamines, but they are nonfunctional in most cases. Up to 50% of patients with paragangliomas are asymptomatic and the diagnosis is incidental [2–4]. Clinical symptoms may be related to catecholamine hypersecretion (hypertension or hyperhidrosis) or to a mass effect resulting in complaints of hoarseness, dysphagia, shortness of breath, and chest pain [2–4]. A review of the literature identified only 11 cases of purely tracheal paraganglioma, with a propensity for the tumor to arise from the membranous trachea, as in our case [3, 4]. Tracheal paragangliomas, which are typically very vascular, usually present with hemoptysis, and biopsy may be difficult because of bleeding. When preoperative biopsy is considered, optimal diagnostic management should include the involvement of a thoracic surgeon and the availability of complex airway management techniques, including rigid bronchoscopy. Paragangliomas have typical characteristics on CT and MRI. They are usually located at the bifurcations of great vessels and show intense homogeneous enhancement except in

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necrotic areas, which enhance poorly. These tumors show intermediate signal intensity on T1weighted MR images and high signal intensity on T2-weighted images [3, 4]. When appropriate, 123I-metaiodobenzylguanidine scintigraphy and PET/CT with 18F-FDG are used for the localization and staging of paragangliomas [3, 4]. Thus, we suggest that paraganglioma should be included in the differential diagnosis of a contrast-enhanced mass in the trachea. Bruno Hochhegger Marcos Duarte Guimaraes Edson Marchiori Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil DOI:10.2214/AJR.13.11764 WEB—This is a web exclusive article.

References 1. Ngo AV, Walker CM, Chung JH, et al. Tumors and tumorlike conditions of the large airways. AJR 2013; 201:301–313 2. Young WF Jr. Paragangliomas: clinical overview. Ann N Y Acad Sci 2006; 1073:21–29 3. Balcombe J, Torigian DA, Kim W, Miller WT Jr. Cross-sectional imaging of paragangliomas of the aortic body and other thoracic branchiomeric paraganglia. AJR 2007; 188:1054–1058 4. McCall JW, Karam FK. Chemodectoma of the trachea. AMA Arch Otolaryngol 1958; 67:372–373

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Fig. 1—35-year-old man with tracheal paraganglioma. A and B, Unenhanced CT images show mass in posterior wall of cervical trachea. C and D, Contrast-enhanced CT images show contrast-enhanced mass with necrotic center.

AJR 2014; 202:W1 0361–803X/14/2026–W1 © American Roentgen Ray Society

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AJR:202, June 2014

Tracheal paraganglioma: differential diagnosis of a contrast-enhanced tracheal mass.

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