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INTRODUCTION Mature teratomas are the most common mediastinal germ

cell tumors. Most mature teratomas are located in the anterior mediastinum, and only 3–8% of mature teratomas occur in the posterior mediastinum (1). Mature teratomas may rarely rup-ture into adjacent structures (2). Based on a review of the litera-ture, ruptured mature teratomas in the posterior mediastinum have not been reported previously. Ruptured teratomas with in-vasion of adjacent structures, such as the pleural space, pericar-dium, or lung parenchyma, have rarely been reported, but all re-ported mediastinal mature teratomas have been located in the anterior mediastinum (2).

In this case report, we noted an unusual tumor location and imaging findings of ruptured mature teratomas in the mediasti-num. We present a case of ruptured mature cystic teratoma lo-cated in the posterior mediastinum with fistula formation of the

adjacent lung and esophagus.

CASE REPORT

A 43-year-old-man presented to our outpatient clinic to eval-uate hemoptysis of 1-week duration. He also complained of dys-phagia and vigorous cough during meals. He had a history of bronchiectasis diagnosed at 15-years-of-age. The physical exam-ination revealed coarse and diminished breath sounds over the right lower chest. The results of laboratory tests, including com-plete blood count, chemistry panel, and serum tumor markers were normal.

Chest posteroanterior radiograph showed consolidation in the right lower lung field and curvilinear opacities along the lower thoracic spine superimposed on the right atrium and left heart border, findings suggestive of a posterior mediastinal mass (Fig. 1). Chest computed tomography (CT) revealed a large het-

Case ReportpISSN 1738-2637 / eISSN 2288-2928J Korean Soc Radiol 2014;70(2):119-122http://dx.doi.org/10.3348/jksr.2014.70.2.119

Received October 18, 2013; Accepted October 21, 2013Corresponding author: Hyo Lim Kim, MDDepartment of Radiology, Yeouido St. Mary’s Hospital, The Catholic University of Korea College of Medicine, 10 63-ro, Yeongdeungpo-gu, Seoul 150-713, Korea.Tel. 82-2-3779-1271 Fax. 82-2-783-5288 E-mail: horrim@hanmail.net

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distri-bution, and reproduction in any medium, provided the original work is properly cited.

Mature teratomas are rarely located in the posterior mediastinum, and most mature teratomas are asymptomatic. Teratoma rupture into the adjacent lung and esopha-gus is possible but considering the rare entity of posterior mediastinal teratomas and the perforation rate, it is extremely unusual. We report a case of ruptured ma-ture cystic teratoma located in the posterior mediastinum, showing fistula forma-tion to the adjacent lung and esophagus, which presented with hemoptysis.

Index termsTeratomaNeoplasmMediastinumChest Imaging

Ruptured Mature Cystic Teratoma in the Posterior Mediastinum: A Case Report1

후종격동에 생긴 파열된 성숙 기형종의 증례 보고1

Jae Sup Jun, MD1, Hyun Jin Park, MD2, Ki Jun Kim, MD3, Jin Young You, MD4, Won Sang Jung, MD2, Deog Gon Cho, MD5, Hyo Lim Kim, MD1 1Department of Radiology, Yeouido St. Mary’s Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea2Department of Radiology, St. Vincent Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea3Department of Radiology, Incheon St. Mary’s Hospital, The Catholic University of Korea College of Medicine, Incheon, KoreaDepartments of 4Pathology, 5Thoracic Surgery, St. Vincent Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea

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Esophagography revealed contrast leakage into the tumor and an irregular surface of the involved distal esophagus (Fig. 3). The bronchoscopy showed a profuse purulent-like secretion at the dis-tal portion of the anterior basal segment of the right lower lobe bronchus. There was no definite fistulous tract on bronchoscopic examination. Polymerase chain reaction analysis of the bronchial wash fluid was negative for Mycobacterium tuberculosis.

A thoracotomy was performed to obtain an adequate tissue sample for a definite diagnosis of the mass and treat the fistula. Intraoperative inspection showed a mass tightly adherent to the right lower lobe and infiltrating into the esophagus. The surgeon confirmed two fistulous tracts connected to the distal esophagus and right lower lung. An excision of the posterior mediastinal tumor and a partial esophagectomy with gastroesophageal re-construction were performed.

The tumor consisted of multiple cystic structures lined by co-lumnar and squamous epithelium, skin appendages with sweat glands and hair follicles, and neural tissue. The mass was patho-logically confirmed as a mature cystic teratoma (Fig. 4).

The patient recovered well and has had no evidence of recur-rence or complications to date. A repeat chest CT obtained 3 months later showed regression of necrotizing pneumonia in the right lower lobe of the lung.

DISCUSSION Teratomas are germ cell tumors composed of several types of

erogeneous mass in the right paraesophageal region below the carina. The mass contained fat, soft tissue, calcifications, fluid, and air bubbles (Fig. 2A, B). Consolidation with an air bronchogram and multi-focal low density areas were seen at the anterior aspect of the right lower lobe. The mediastinal mass and the consolida-tion were in direct contact and an air-containing fistulous tract visible between the mediastinal mass and the consolidation (Fig. 2B). The distal esophagus was displaced to the left side by the mass. Another fistulous tract was noted between the esophagus and the mediastinal mass on the coronal image (Fig. 2C). No pleural or pericardial effusion was present. Esophagography and bronchoscopy were performed to confirm the fistulous tracts.

Fig. 1. Chest posteroanterior radiograph shows homogenous consoli-dation (arrows) in the right lower lung field. Note a curvilinear opaci-ties along the lower thoracic spine superimposed on the right atrium and left heart border (arrowheads), finding suggestive of a posterior mediastinal mass.

Fig. 2. A 43-year-old man with ruptured mature cystic teratoma in the posterior mediastinum.A. Contrast-enhanced chest CT with mediastinal window setting shows a huge heterogeneous density mass (arrows) in posterior mediastinum, containing fat, soft tissue, and calcification (arrowhead). Note fat density lesions (circle) that measures -70 Hounsfield unit in density within the mass.B. Coronal reconstruction of contrast-enhanced chest CT reveals consolidation with air bronchogram and focal low density lesion in basal seg-ment of right lower lobe. An air-containing fistulous tract (black arrow) is seen between the mediastinal mass (white arrows) and the consolida-tion (arrowhead).C. Another fistulous tract (white arrow) is observed between the esophagus (black arrow) and the mediastinal mass (arrowheads).

BA C

Jae Sup Jun, et al

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ma, and liposarcoma (6). In the present case, although imaging findings strongly suggested mature cystic teratoma, our differ-ential diagnoses also included liposarcoma. Liposarcomas rarely occur in the mediastinum (7). Liposarcomas appear on CT scans in homogeneous attenuation with significant amounts of soft tissue within the fatty mass (3). Liposarcomas can show calcifi-cation and ossification (7). CT findings suggesting liposarcomas are poor definition of adjacent mediastinal structures or evi-dence of infiltration or invasion of mediastinal structures (3). In our case, there was no definite evidence of tumor infiltration or invasion into adjacent mediastinal structures.

Open thoracotomy and video-assisted thoracoscopic resection are surgical techniques for resecting a mediastinal mature terato-ma (7). When mature teratomas rupture, the internal compo-

mature or immature somatic tissues derived from two or three germinal layers. They are classified as mature, cystic (dermoid cyst), immature, and malignant (3).

Patients with mature teratomas are usually asymptomatic and the masses are found incidentally on a chest radiograph. Patients may have symptoms such as cough, chest pain, dyspnea or he-moptysis resulting from local compression, associated infection, or rupture (2). Mature teratomas may rarely rupture into adja-cent structures such as the pleural space, pericardium, lung pa-renchyma, or tracheobronchial tree (2). The mechanism of rup-ture of a mature teratoma is still controversial, although autolysis, chemical inflammation, ischemia, pressure necrosis, and infec-tion have been proposed (2). Pericardial effusion, pleural effu-sion, lipoid pneumonia, or expectoration of hair or sebaceous materials may occur in patients with a ruptured teratoma (1).

Imaging features of unruptured mature teratomas in the poste-rior mediastinum are identical to typical anterior mediastinal teratomas, except for the location (2, 4). The most frequent CT manifestation of an unruptured mature teratoma in the medias-tinum is a heterogeneous mediastinal mass, containing soft tis-sue, fluid, fat, and calcifications (1). Calcification is observed in about 50% of cases, being focal or rimlike or rarely teeth or bone.

The most significant imaging findings of ruptured masses are inhomogeneity of the internal components. The heterogeneous densities of the ruptured tumors might be caused by the mixing of internal components in different compartments with a second-ary inflammatory reaction to extravasated contents (2). Some an-cillary findings such as a fat-containing mass, consolidation, or atelectasis in the adjacent lungs are helpful for detecting ruptured teratomas. Other findings to detect rupture of the tumor are pleural and pericardial effusions (2). In our case, image findings such as heterogeneous densities of the mass, consolidation in the adjacent lung, and fistula formation of the adjacent esophagus raise the possibility of ruptured mature cystic teratoma into the adjacent lung and esophagus.

The differential diagnosis of posterior mediastinal tumors in-cludes neurogenic tumor, bronchogenic cyst, enteric cyst, xan-thogranuloma, diaphragmatic hernia, esophageal tumor, lymph-adenopathy from granulomatous disease, and paravertebral abscess (5). When fat-containing lesions with calcification are detected in the posterior mediastinum, the differential diagnosis includes germ cell tumors, extramedullary hematopoiesis, lipo-

Fig. 3. Esophagography reveals contrast leakage (arrow) into the tu-mor, suggesting communication between the tumor and esophagus.

Fig. 4. Microscopic image of the mass shows sweat glands (large ar-row), adipose tissue (small arrow), neural tissue (large arrowhead), and multiple cystic structures lined by columnar (small arrowhead) and squamous epithelium (hematoxylin and eosin stain, × 40).

Ruptured Mature Cystic Teratoma in the Posterior Mediastinum

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mors: radiologic and pathologic correlation. Radiographics

1992;12:1013-1030

2. Choi SJ, Lee JS, Song KS, Lim TH. Mediastinal teratoma: CT

differentiation of ruptured and unruptured tumors. AJR

Am J Roentgenol 1998;171:591-594

3. Muller NL, Silva CIS. Imaging of the chest. Philadelphia,

PA: Saunders/Elsevier, 2008

4. Sinclair DS, Bolen MA, King MA. Mature teratoma within the

posterior mediastinum. J Thorac Imaging 2003;18:53-55

5. Duwe BV, Sterman DH, Musani AI. Tumors of the medias-

tinum. Chest 2005;128:2893-2909

6. Moran CA, Suster S, Fishback N, Koss MN. Extramedullary

hematopoiesis presenting as posterior mediastinal mass: a

study of four cases. Mod Pathol 1995;8:249-251

7. Shintani Y, Funaki S, Nakagiri T, Inoue M, Sawabata N, Min-

ami M, et al. Experience with thoracoscopic resection for

mediastinal mature teratoma: a retrospective analysis of 15

patients. Interact Cardiovasc Thorac Surg 2013;16:441-444

nents of the teratoma such as proteolytic or digestive enzymes leak into the adjacent organs, causing inflammation and adhe-sions. Therefore, surgical treatment of ruptured tumors is more complicated than unruptured tumors (2). In our patient, severe adhesions and inflammation were present between the tumor and adjacent esophagus, so the surgeon performed a mediasti-nal tumor resection and partial esophagectomy with gastro-esophageal reconstruction.

In conclusion, early diagnosis of ruptured mature teratomas is important for proper management. Understanding the radio-logic findings of ruptured teratomas and the unusual tumor lo-cation can improve the correct diagnosis rate for ruptured pos-terior mediastinal mature teratomas.

REFERENCES

1. Rosado-de-Christenson ML, Templeton PA, Moran CA.

From the archives of the AFIP. Mediastinal germ cell tu-

후종격동에 생긴 파열된 성숙 기형종의 증례 보고1

전재섭1 · 박현진2 · 김기준3 · 유진영4 · 정원상2 · 조덕곤5 · 김효림1

성숙 기형종은 드물게 후종격동에서 생기며, 증상 없이 우연히 발견되는 경우가 많다. 기형종은 인접한 폐나 식도로 파열

될 수 있는데, 후종격동에 생기는 기형종이 드물고 낮은 파열 빈도를 고려하였을 때, 후종격동 기형종의 파열은 극히 드문

예라 할 수 있다. 저자들은 후종격동에 생긴 성숙 기형종이 파열되어 인접한 폐와 식도로 누공을 형성한 증례를 경험하였

기에 보고하는 바이다.

1가톨릭대학교 의과대학 여의도성모병원 영상의학과, 2가톨릭대학교 의과대학 성빈센트병원 영상의학과, 3가톨릭대학교 의과대학 인천성모병원 영상의학과, 가톨릭대학교 의과대학 성빈센트병원 4병리과, 5흉부외과