|Year : 2015 | Volume
| Issue : 4 | Page : 213-216
Excision of benign mature anterior mediastinal teratoma through trapdoor incision: A case report with review of literature
Pankaj Srivastava1, Manoj Kumar Srivastava2, Shalini Srivastava3, Sandeep Roshan4
1 Department of Surgery, Om Surgical Center and Maternity Home, Varanasi, Uttar Pradesh, India
2 Department of Medicine, Om Surgical Center and Maternity Home, Varanasi, Uttar Pradesh, India
3 Department of Obstetrics and Gynecology, Om Surgical Center and Maternity Home, Varanasi, Uttar Pradesh, India
4 Department of Radiodiagnosis, Sirona Diagnostika, Varanasi, Uttar Pradesh, India
|Date of Web Publication||21-Jan-2016|
Dr. Pankaj Srivastava
Om Surgical Center and Maternity Home, Sri Krishna Nagar, Paharia, Ghazipur Road, Varanasi - 221 007, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
A 20-year-old female presented with right-sided chest pain with nonproductive cough. Contrast enhanced computed tomography (CECT) thorax showed well-defined nonenhancing soft tissue density lesion in the anterior mediastinum with the presence of multiple small well-defined cystic lesions showing fat density as well as multiple calcifications within it suggestive of a teratoma. The patient underwent surgical excision of the tumor via a trapdoor incision and the final diagnosis of benign mature cystic teratoma was made. The follow-up of two years was uneventful.
Keywords: Germ cell and embryonal, germ cell tumor, median sternotomy, mediastinal neoplasms, mediastinal tumor, teratoma, thoracotomy, trapdoor incision, sternothoracotomy
|How to cite this article:|
Srivastava P, Srivastava MK, Srivastava S, Roshan S. Excision of benign mature anterior mediastinal teratoma through trapdoor incision: A case report with review of literature. Arch Int Surg 2015;5:213-6
|How to cite this URL:|
Srivastava P, Srivastava MK, Srivastava S, Roshan S. Excision of benign mature anterior mediastinal teratoma through trapdoor incision: A case report with review of literature. Arch Int Surg [serial online] 2015 [cited 2019 Aug 24];5:213-6. Available from: http://www.archintsurg.org/text.asp?2015/5/4/213/174667
| Introduction|| |
The mediastinum is the most common extragonadal site of germ cell tumors and represent approximately 1-3% of all germ cell neoplasms.  These are classified into three categories: Benign germ cell tumors (teratomas), seminomas, and nonseminomatous germ cell tumors, which are also called malignant teratomas.  Histologically teratomas are further divided into mature, immature, and teratoma with malignant components. Mature teratomas are commonly cystic and possess well-differentiated tissues from the three germinal cell layers. They often include cartilage or adipose tissue, glandular epithelium, and squamous epithelium. Malignant transformation of teratoma in the anterior mediastinum is rare.  Complete surgical resection is the treatment of choice for benign teratomas. A median sternotomy, ministernotomy, posterolateral thoracotomy, hemiclamshell thoracotomy with or without neck extension, clamshell, and video-assisted thoracic surgery (VATS) are described methods for resection.
| Case Report|| |
A 20-year-old Indian female (weight 66 kg, height of 157 cm) presented with chest pain mainly on right side with occasional nonproductive cough of 6 months duration. There was no history of smoking, tobacco addiction, tuberculosis, or any significant chest disease. The chest X-ray showed relatively homogeneous lobulated opacity with air lucency within it in the anterior mediastinum obscuring the right cardiac border [Figure 1]. Contrast enhanced computed tomography (CECT) of the thorax showed well-defined nonenhancing soft tissue density lesion of 97 mm × 52 mm × 60 mm in the anterior mediastinum with the presence of multiple small well-defined cystic lesions showing fat density as well as multiple calcifications within it [Figure 2]. Bronchoscopy revealed no intraluminal growth and no bronchial compression at any level. Bronchoalveolar lavage smears were negative for malignant cells. Ultrasonography of abdomen and pelvis revealed no evidence of any intra-abdominal abnormality, adnexal mass, ascites, and pelvic collection. M-mode and 2D-Echo color Doppler findings suggestive of mild tricuspid regurgitation and trace pulmonary regurgitation with normal left ventricular ejection fraction of 59%. Pulmonary function test (PFT) revealed mild obstruction (FEV1/FVC = 83.36%, predictive value = 89.59%). Serum-β human chorionic gonadotropin (β-hCG), serum lactate dehydrogenase (LDH), and serum alpha-fetoprotein (AFP) levels were within normal range of 1.1 mIU/L, 204 U/L, and 1.55 ng/mL, respectively. All other hematologic parameters were within normal limits.
|Figure 1: Pre-operative chest x-ray (PA view) showed large homogenous lobulated opacity with lucency within it in anterior mediastinum obscuring right cardiac border and follow-up Chest X-ray (PA View) after 1 month revealed no abnormality|
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|Figure 2: CECT of thorax showed a well-defined, nonenhancing soft tissue density lesion (97 mm × 52 mm × 60 mm) in the anterior mediastinum with multiple small well-defined cystic lesions showing fat density as well as multiple calcifications suggesting teratoma|
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Since the mediastinal tumor markers were normal and the CECT findings were strongly suggestive of benign teratoma, a complete resection was planned. By keeping in mind the position and size of the tumor, excision of the mass was decided through hemiclamshell thoracotomy without neck extension, commonly known as "trapdoor" incision, i.e., partial vertical median sternotomy combined with an anterior thoracotomy in the fifth intercostal space.
After general anesthesia and intubation with single lumen endotracheal tube, the patient was put in supine position. A right anterior thoracotomy was planned through inframammary skin incision so as to avoid postoperative visible scar marks and further damage to breast tissue though right pleural space was entered through the fifth intercostal space. After completing the anterior thoracotomy and ligation of right internal mammary artery, a vertical median sternotomy was performed that then combined with anterior thoracotomy through the fifth intercostal space [Figure 3]. After meticulous dissection, chest wall was retracted to explore the tumor that was found densely adhered with all the surrounding structures. The adhesions between tumor mass and underlying visceral pleura, the pericardium, the right phrenic nerve, the diaphragm were carefully separated uneventfully by blunt and sharp dissection. Tumor mass was then dissected out from its bed after achieving proper hemostasis [Figure 4]. The tumor, excised en bloc, was grayish-black colored, well-circumscribed, thick capsuled, and having cystic-solid consistency with bosselated surface; the cut section of which showed distorted gray brown tissue mass with cystic areas filled with putty like material, hair, and solid areas [Figure 5]. The right hemithorax was thoroughly washed with lukewarm saline and checked for any air leak. A 28 Fr chest tube was placed at wound site. Median sternotomy was closed with no. 6 steel wire and anterior thoracotomy was closed with multiple no. 1 loop nylon pericostal sutures. Rest of the wound was closed in layers [Figure 3]. One 28 Fr chest tube was also placed on left side due to inadvertent opening of the left mediastinal pleura during dissection. The patient was successfully extubated postoperatively. Minor air leak was present initially on right side that subsided by day 4. Left chest tube was taken out on day 3 and right chest tube on day 10 when full lung expansion was achieved. Histopathological examination revealed keratinous cyst with sebaceous glands, cartilage, nerve bundles, ganglion cells, fibroadipose tissue, intestinal glands, respiratory epithelium, salivary gland tissue, and lymphocytic infiltrate suggestive of mature cystic teratoma with no evidence of malignancy. Postoperative recovery was uneventful and 2-year follow-up was satisfactory with no evidence of recurrence of disease.
|Figure 3: Skin incision just after closure and after follow-up of 1 month|
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|Figure 4: Right hemithorax before and after excision of the tumor. T = Tumor, B = Tumor base, L = Lung, H = Heart|
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|Figure 5: Excised whole tumor and its cut section showed tumor with hairs and multiple cystic areas filled with putty-like material|
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| Discussion|| |
The most common tumors found in the anterior mediastinal compartment are of thymic, lymphatic, or germ cell origin. About 85% of germ cell tumors are benign in nature and affect both sexes equally in their second and fourth decades of life. Malignant germ cell tumors occur predominantly in male patients.  The most common histologic type of mediastinal germ cell tumor is mature teratoma followed by seminoma.  Mature teratomas commonly are cystic and possess well-differentiated tissues from all the three germinal cell layers and often include teeth, cartilage, adipose tissue, glandular epithelium, and squamous epithelium. Tumor markers like alpha-fetoprotein, beta β-hCG, and LDH are usually not elevated. Majority of patients have no signs or symptoms when the mass is initially diagnosed. Symptoms commonly present are chest, back, or shoulder pain; dyspnea; cough; fever; pleural effusion; and bulging of the chest wall.  The typical radiographic appearance of mature teratoma is that of a rounded, sometimes lobulated anterior mediastinal mass with the borders of the mass sharply marginated against the adjacent lung.  CT is the diagnostic test of choice for the evaluation of mediastinal masses. It exquisitely shows the location and extent of the tumors as well as intrinsic elements including soft tissue (~100%), fat (76%), fluid (88%), and calcification (53%), and teeth and such imaging findings are considered specific. , Mediastinal mature teratomas typically manifest on CT as heterogeneous sharply marginated, spherical, or lobulated anterior mediastinal masses containing soft tissue, fluid, fat, or calcium attenuation, or any combination of the four. Magnetic resonance imaging (MRI) is superior to the CT scan for the evaluation of masses located at the thoracic inlet or at the thoracoabdominal level and especially tumors closely associated with the heart. MRI is sensitive in depicting the infiltration of adjacent structures by fat plane infiltration. 
Surgical resection is the treatment of choice for most mediastinal tumors, except for malignant germ cell neoplasms. For mature teratomas, complete excision of the mass is generally sufficient. Median sternotomy is usually preferred for the removal of anterior mediastinal masses; however, additional exposure, including hemiclamshell thoracotomy with or without neck extension, may be preferred for tumors in the anterior mediastinum with extensive involvement of the hemithorax. In the present case, we opted for a partial vertical median sternotomy combined with right anterior thoracotomy in the fifth intercostal space [Figure 3]. Grillo has proposed this incision for lower tracheal resections and coined the term "trapdoor incision".  This approach facilitated a complete excision of the mass that was densely adhered to the surrounding structures including heart and right phrenic nerve. In conclusion, teratomas can easily be diagnosed and treated successfully by complete excision with favorable long-term prognosis. The trapdoor incision is a straightforward and viable approach for surgical excision of large anterior mediastinal teratomas.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]