SESSION TYPE: Miscellaneous Student/Resident Case Report Posters
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: Thymic masses are commonly found in the anterior mediastinum accounting for almost 13% of all mediastinal masses (1) Thymic cysts compromise 5% of all mediastinal cysts and 1% of all mediastinal masses, they can rarely be found in the other mediastinal compartments, with only few cases reporting middle mediastinal thymic cysts and one case report on a posterior mediastinal thymic cyst. (1,2)
CASE PRESENTATION: A 64 year old woman with history of asthma presented after a syncopal episode no associations no seizure activity. Vital signs were normal, no neck masses or thyromegaly, unremarkable lung and heart exams with grossly intact neurological exam. Inital laboratory and imaging results were unremarkable. A 2D- transthoracic echocardiogram and CT scan of the chest with intravenous contrast are shown below. A right sided Video Assisted Thoracoscopy (VATS) was performed with resultant aspiration of the cystic fluid and de-roofing of the cystic lesion; biopsy showed a cyst wall devoid of lining with calcification, ossification and cholesterol clefts. The cyst wall has lymphoid tissue, compatible with thymic cyst; cytological analysis of the aspirated fluid was negative for malignancy.
DISCUSSION: Anterior prevascular compartment of the mediastinum is the most common site for thymic masses which account for 13% of all mediastinal masses. Thymic cystic lesions are even rarer and compromises 5% of all mediastinal cysts and 1% of all mediastinal tumors. During the process of intrauterine development, it is possible that accessory thymic lobes show aberrant migration with the resultant thymic tissue in abnormal sites. Minniti et.al, reported two cases of middle mediastinal thymic masses both were asymptomatic one of which was a thymic cyst. (1) Ertugrul et.al in their six case series had found five cases anterior mediastinal and one upper mediastinal thymic cyst most were symptomatic with either dyspnea, hemoptysis or chest pain.(3)
CONCLUSIONS: Whereas thymic solid masses like thymomas can be relatively found more common in other mediastinal compartment, thymic cysts are rarely found in such locations. There is only one report as far as our best knowledge of thymic cysts in the posterior mediastinal compartment with only few reported cases of thymic cyst arising in the middle mediastinal compartment. Our patient presented with a single episode of syncope found to have posterior mediastinal thymic cyst
1) Minnit Si, Valentini M, Pinali L, MalagoR Lestani M, Procacci C. Thymic Masses of the Middle Mediastinum Report of 2 Cases and Review of the Literature. J Thorac Imaging Volume 19, Number 3, July 2004 192-195
2) Strollo DC, Rosado-de-Christenson ML, Jett JR Primary Mediastinal Tumors : Part II. Tumors of the Middle and Posterior Mediastinum Chest 1997;112;1344-1357
3) Ertugrul M, Bayram U, Damadoglu E, Arnic S, Sulu E, Yagci L, Atasalihi A, Yilmaz A. Thymic cysts: A report of six cases Tüberküloz ve Toraks Dergisi 2006; 54(2): 172-176.
DISCLOSURE: The following authors have nothing to disclose: Hayder Hashim, Rend Al-Khalili, James Maher
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