Chest imaging
Case TypeClinical Cases
Authors
Aditya Mehta, Ami Bhalodia
Patient30 years, female
A 30-year-old female presented to the chest clinic with gradual onset of chest pain and discomfort. For an initial evaluation, a frontal chest radiograph was ordered which was showing asymmetrically widened mediastinal borders, especially in the right paramedian location (not available at the moment). Later on, to characterize the lesion, a contrast-enhanced computed tomography scan of the thorax was ordered to rule out differentials of mediastinal widening.
Contrast-enhanced CT scan images were showing a well-defined well marginated encapsulated large cystic lesion, which was situated along the right-sided margins of the anterior and middle mediastinum. It appears to be abutting the right atrium, superior vena cava, and reaching up to the hilar region. There is the presence of another well-defined well-marginated fat-containing rounded lesion with an internal non-enhancing mural nodule noted within the cystic lesion. Few fat densities in scattered areas were noted along the superior aspect of the lesion. No calcification foci were noted within the lesion. The wall of the lesion shows minimal faint enhancement. No enlarged mediastinal lymph nodes or any metastatic thoracic and upper abdominal lesions were noted.
The above findings favour a mature type of cystic teratoma without calcification.
Benign mature teratomas are tumours that belong to the group of germ cell tumours, typically occur in young patients and have an approximately equal sex ratio. They are derived from primitive cells that fail to migrate completely during early embryonic development. They predominantly consist of ectodermal elements including skin, sebaceous gland, hair and calcification.
Mediastinal teratomas account for 10-20% of all mediastinal tumours and are usually found in the anterior mediastinum [1]. Other anterior mediastinal tumours are thymoma, thymolipoma, lymphoma, thyroid lesions, aneurysm of thoracic aorta. Most patients are completely asymptomatic as the tumour grows slowly. As they enlarge they may cause symptoms by compressing surrounding structures. Extrinsic compression of the heart and great vessels appears to be very rare [2, 3]. Benign teratomas do have the potential to undergo malignant transformation into a variety of malignancies as rhabdomyosarcoma, adenocarcinoma, leukaemia and anaplastic small cell tumours [4].
Diagnostic assessment of mediastinal tumours is performed with plain chest radiographs and chest CT. Although the presence of fat and calcification within an anterior mediastinal mass suggests a teratoma, the preoperative diagnosis is often difficult on plain films because of the inability to detect the fat or calcification. CT accurately estimates the density of all included tissues, such as soft tissue (in virtually all cases), fluid (88%), fat (76%), calcification (53%) and teeth, which are considered specific imaging findings [5, 2]. MRI is a very valuable tool in detecting the anatomical relations to the mediastinal and the hilar structures, like vessels and airways. A large anterior mediastinal mass with a well-defined wall and predominantly cystic component are highly suggestive of a benign cystic teratoma. With calcifications in the wall of the mass or small spherical or irregular calcifications within the mass, mature cystic teratoma is even more likely. Unequivocal fat within the mass, particularly a fat-fluid level, makes this diagnosis certain.
Complete surgical resection is the treatment of choice, but also subtotal resection can relieve symptoms. There is a role of transthoracic biopsy only if lesion is adjacent to bronchus but in our case, it was far away and predominantly in anterior mediastinum therefore only excisional biopsy was preferred.
Teaching points/Take-home message
From the above case, one can learn that; mature teratoma may present without calcification or tooth which along with fat is a very certain finding generally, therefore this case is an exception to general behaviour.
Written informed patient consent for publication has been obtained.
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[2] Rosado-de-Christenson ML, Templeton PA, Moran CA (1992) From the archives of the AFIP. Mediastinal germ cell tumors: radiologic and pathologic correlation. Radiographics 12(5):1013-30 (PMID: 1326777).
[3] Erasmus JJ, Page McAdams H, Donnelly LF, Spritzer CE (2000) MR imaging of mediastinal masses. MRI clinics of North America 8/1:59-84 (PMID: 10730236).
[4] No T-H, Seol S-H, Seo G-W, Kim D-I, Yang SY, Jeong CH, Hwang Y-H, Kim JY (2015) Benign Mature Teratoma in Anterior Mediastinum. J Clin Med Res 7(9):726–728. doi: 10.14740/jocmr2270w (PMID: 26251691) (PMCID: PMC4522994).
[5] Ramcharran H, Wallen J (2022) J Cardiothorac Surg 17:67. doi: 10.1186/s13019-022-01806-w (PMCID: PMC8985258).
URL: | https://www.eurorad.org/case/18054 |
DOI: | 10.35100/eurorad/case.18054 |
ISSN: | 1563-4086 |
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