Distribution of mediastinal ectopic thymic tissue in patients without thymic disease

Authors
Behnam Sanei 1
Seid Abbas Tabatabie 1
Hamid Bigdelian 1
Seid Mozafar Hashemi 1
Amir Hossein Davarpanah 1
Hamid Reza Jafari 2
Mohammad Hossein Sanei 3
1 Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran
2 Medical Student Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
3 Department of Pathology, Acquired Immunodeficiency Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
Abstract
Background: Different approaches to treat myasthenia gravis showed variable outcomes probably because of remained ectopic thymic tissue. The aim of this study is to determine incidence of thymic tissue in cases without any thymic disease.
Materials and Methods: Seventy-two patients scheduled for open heart surgery during 2000 and 2007 without thymic disease that were enrolled in the study at Chamran Hospital. Intraoperative biopsies were taken form aortopulmonary window, aortocaval groove and left and right pericardiophrenic regions. Finally, the distribution of ectopic thymic tissue was evaluated in above regions.
Results: Thymic tissue was found overall in 70.85% of patients. The most common sites for thymic tissue were left pericardiophrenic (50%) and right pericardiophrenic (31.9%) regions. Frequencies of ectopic thymus in aortopulmonary window and aortocaval groove were 19.4% and 12.5%, respectively.
Conclusion: Because of high incidence of ectopic thymic tissue in mediastinum in patients without thymic disease, we recommend wide excision of thymus gland and all of adipose tissue in patients with myasthenia gravis.
Keywords
Ectopic thymic tissue
mediastinum
myasthenia gravis
1.
Moore KL, Persaud TV. The developing human. Clinically Oriented Embryology. 9 th ed. Philadelphia: WB Saunders Company; 2011. p. 167,173.  Back to cited text no. 1
    
2.
Fukuda T, Itami M, Sawa H, Furukawa T, Fukakusa S, Tsuchihashi N, et al. A case of thymoma arising from undescended thymus. High uptake of Thallium-201 chloride. Eur J Nucl Med 1980;5:465-8.  Back to cited text no. 2
    
3.
Miller WT Jr, Gefter WB, Miller WT. Thymoma mimicking a thyroid mass. Radiology 1992;184:75-6.  Back to cited text no. 3
    
4.
Kiyosue H, Miyake H, Komatsu E, Mori H. MRI of cervical masses of thymic origin. J Comput Assist Tomogr 1994;18:206-8.  Back to cited text no. 4
    
5.
Yamashita H, Murakami N, Noguchi S, Noguchi A, Yokoyama S, Moriuchi A, et al. Cervical thymoma and incidence of cervical thymus. Acta Pathol Jpn 1983;33:189-94.  Back to cited text no. 5
    
6.
Khariwala SS, Nicollas R, Triglia JM, Garabedian EN, Marianowski R, Van Den Abbeele T, et al. Cervical presentations of thymic anomalies in children. Int J Pediatr Otorhinolaryngol 2004;68:909-14.  Back to cited text no. 6
    
7.
Tabatabaie SA, Hashemi SM, Sanei B, Sanei MH. The frequency of ectopic thymic tissue in the necks of patients without any thymic disease. Med Sci Monit 2007;13:CR283-5.  Back to cited text no. 7
    
8.
Zieliñski M, Kuzdzal J, Szlubowski A, Soja J. Comparison of late results of basic transsternal and extended transsternal thymectomies in the treatment of myasthenia gravis. Ann Thorac Surg 2004;78:253-8.  Back to cited text no. 8
    
9.
Fukai I, Funato Y, Mizuno T, Hashimoto T, Masaoka A. Distribution of thymic tissue in the mediastinal adipose tissue. J Thorac Cardiovasc Surg 1991;101:1099-102.  Back to cited text no. 9
    
10.
Jaretzki A 3 rd , Wolff M. "Maximal" thymectomy for myasthenia gravis. Surgical anatomy and operative technique. J Thorac Cardiovasc Surg 1988;96:711-6.  Back to cited text no. 10
    
11.
Masaoka A, Yamakawa Y, Niwa H, Fukai I, Kondo S, Kobayashi M, et al. Extended thymectmy for myasthenia gravis patients: A 20-year review. Ann Thorac Surg 1996;62:853-9.  Back to cited text no. 11
    
12.
Ambrogi V, Mineo TC. Active ectopic thymus predicts poor outcome after thymectomy in class III myasthenia gravis. J Thorac Cardiovasc Surg 2012;143:601-6.  Back to cited text no. 12
    
13.
Mineo TC, Ambrogi V. Outcomes after thymectomy in class I myasthenia gravis. J Thorac Cardiovasc Surg 2013;145:1319-24.  Back to cited text no. 13
Advanced Biomedical Research
Volume 2015, January
January 2015
Pages 1-3