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 Table of Contents     
Year : 2017  |  Volume : 13  |  Issue : 4  |  Page : 286-290

Is a diagnostic video-assisted thoracoscopic thymectomy an acceptable first-line approach to the suspicious anterior mediastinal mass?

Department of Thoracic Surgery, Glenfield Hospital, Leicester, LE3 9QP, UK

Date of Submission08-Jun-2015
Date of Acceptance02-Mar-2017
Date of Web Publication5-Sep-2017

Correspondence Address:
Ricky Vaja
Department of Thoracic Surgery, Glenfield Hospital, Groby Road, Leicester, LE3 9QP
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jmas.JMAS_113_15

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 ¤ Abstract 

Introduction: The incidental early-stage thymic mass presents a diagnostic challenge. Video-assisted thoracoscopic (VAT) thymectomy is an attractive but potentially morbid solution. The aim was to show it can be safely applied as a first-line modality in those with undiagnosed thymic enlargement with acceptable long-term results.
Methods: A total of 45 patients were identified (24 male, median age 52 interquartile range [IQR]: 41–66 years) in a 14-year experience who had CT evidence of an enlarged, possibly malignant thymic mass, but no tissue diagnosis before undertaking VAT thymectomy. The clinical outcomes of both benign and malignant diagnoses were compared.
Results: Myasthenic symptoms were present in 20 patients (44%), whereas 15 (33%) were asymptomatic. Benign lesions were resected in 27 patients (60%): thymic hyperplasia (56%), thymic cyst (33%), lipoma (7%) and xanthogranulomatous inflammation (4%). Of the 18 malignant patients, 82% had thymoma (three had Masaoka Stage I, 11 Stage II and one Stage III), 6% thymic carcinoma, 6% teratoma and 6% seminoma. Seven patients required radiotherapy for R1 resection. There was no difference in median hospital stay in either group: Benign group: 4 versus 5 days (P = 0.07). One patient in both groups required conversion to open. Two patients in the malignant group had significant morbidity (one myocardial infarction and one pulmonary embolism). There were no cases of tumour recurrence or mortality at a median follow-up of 6.6 years (IQR: 4.4–9.5 years).
Conclusion: Right-sided diagnostic VAT thymectomy is a safe and effective first-line approach to suspected malignant thymic enlargement. At 5-year follow-up, there were no cases of recurrence in the malignant group.

Keywords: Thymectomy, thymoma, video-assisted thoracoscopic

How to cite this article:
Vaja R, Joshi V, Dawson AG, Waller DA. Is a diagnostic video-assisted thoracoscopic thymectomy an acceptable first-line approach to the suspicious anterior mediastinal mass?. J Min Access Surg 2017;13:286-90

How to cite this URL:
Vaja R, Joshi V, Dawson AG, Waller DA. Is a diagnostic video-assisted thoracoscopic thymectomy an acceptable first-line approach to the suspicious anterior mediastinal mass?. J Min Access Surg [serial online] 2017 [cited 2021 Dec 6];13:286-90. Available from:

 ¤ Introduction Top

Thymoma is an uncommon mediastinal tumour with an overall incidence of 0.15 cases per 100,000.[1] It has an established relationship with myasthenia gravis and is present in up to 15% of these patients.[2] Although one-third of all patients with thymoma are symptomatic, the incidental early-stage anterior mediastinal mass is not uncommon and presents a diagnostic challenge.

Computed tomography-guided biopsy (CTGB) is an established diagnostic modality for the exclusion of nonsurgical diagnosis such as lymphoma, but there is controversy for its role in the management of early-stage thymoma. Thoracoscopic approaches to thymectomy including video-assisted thoracoscopic (VAT) thymectomy were first reported by Sugarbaker in 1993.[3] It has become increasingly popular over the past 10 years and is a safe and feasible option in patients with a histologically proven thymoma.[4] However, there is little evidence for the first-line use of VAT thymectomy not only to obtain histological diagnosis but also for therapeutic resection. This is an attractive but a potentially morbid solution as it is associated not only with immediate complications necessitating sternotomy but also with tumour recurrence.

 ¤ Methods Top

Between May 2000 and October 2013, totally 42 patients underwent a VAT surgery (VATS) thymectomy for a thymic mass visualised on contrast-enhanced computerised tomographic scanning without a formal preoperative diagnosis. Patient demographics were obtained from review of both case notes and histological reports. Prospective data regarding patient survival were obtained through our hospital electronic patient records. All patients had preoperative radiological evidence of an anterior mediastinal mass suspicious of thymoma on contrast-enhanced computerised tomography. We excluded patients who had an open transsternal approach (51 patients) and patients with tissue diagnosis before undertaking VAT thymectomy (23 patients). Data were analysed using the Statistical Package for the Social Sciences Version 20.0 software (IBM Corporation, Armonk, NY, USA). Continuous variables were analysed using Mann–Whitney U-tests and categorical variables were analysed using either the Pearson's Chi-square test or Fisher's exact test.

All procedures were carried out by a single surgeon. A double lumen endotracheal tube was used to allow for left lung isolation. A right-sided approach was undertaken for all procedures. The patients were positioned in a 45° lateral-supine position with the ipsilateral arm held in adduction above the patients' head to allow full exposure to the axilla and anterior chest. An attempt to achieve complete resection of the tumour was made in all cases, but total excision of all mediastinal tissue was not performed. The camera port is inserted through a 10 mm port in the 5th intercostal space in the anterior axillary line. Two further 5 mm working ports are inserted as demonstrated in [Figure 1]. A single drain, directed cranially, is placed through one of the ports on completion.
Figure 1: Patient position and port placement for right-sided video-assisted thoracoscopic thymectomy

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 ¤ Results Top

The median age was 52 years (interquartile range [IQR]: 41–66 years) and 24 patients (53%) were male. The majority of patients presented with symptoms (n = 30, 67%), whereas 15 (33%) were asymptomatic. Patients were categorised in either a benign or malignant group based on their final histology and outcomes were compared.

Twenty-seven patients (60%) had a final diagnosis of a benign thymic mass following VATS thymectomy. The median age was 44 years (IQR: 34–60 years) and 52% were male. Eighteen patients (40%) had a malignant lesion identified on final histology. The median age was 64 years (IQR: 52–70 years, P < 0.001) and 56% were male. Fifteen patients presented with symptoms in the benign group and fourteen in the malignant group. The most common symptoms in both were those related to myasthenia gravis (44% in each group), that is, increased muscle fatigue resulting in ocular symptoms, limb weakness and in severe cases and respiratory muscle weakness. Further data on presenting symptoms are summarised in [Table 1].
Table 1: Comparison of the presenting symptoms in the benign and malignant group

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Benign group

The final histology in the benign group was as follows: confirmed thymic hyperplasia 56% (n = 15), thymic cyst 33% (n = 9), lipoma 7% (n = 2,) and xanthogranulomatous inflammation 4% (n = 1). One patient in this group required conversion to an open procedure due to slow progression attributed to multiple adhesions and suboptimal visualisation. There were no surgical-related complications such as bleeding, massive transfusion, organ failure requiring support, prolonged air leak or need for re-exploration. The median hospital length of stay (LOS) was 4 days (IQR: 3–4 days). There were no significant complications or mortality in the benign group on median follow-up of approximately 6.2 years (IQR: 3.4–7.2 years).

Malignant group

The final histology in the malignant group was as follows: Thymoma 82% (n = 15), thymic carcinoma 6% (n = 1), teratoma 6% (n = 1) and seminoma 6% (n = 1). Of those diagnosed with a thymoma, three patients had a Masaoka Stage I, 11 Stage II, and one Stage III. R0 resection was attained in 61% (n = 11) patients with malignant histology. All patients with R1 resection (n = 7, 39%) received postoperative radiotherapy. One patient required conversion to an open procedure anterolateral thoracotomy due to slow progression secondary to multiple adhesions and suboptimal visualisation. Two patients in the malignant group had medical complications (pulmonary embolism and myocardial infarction, P = 0.5). On statistical comparison of age, this group contained a significantly older patient population thus making them more susceptible to such complications. There were no surgical complications in this group with a median LOS of 5 days (IQR: 3–5 days, P = 0.07). There were no cases of mortality or tumour recurrence in the malignant group on a median follow-up of 6.6 years (IQR: 4.4–9.5 years).

 ¤ Discussion Top

The role of VATS thymectomy as both a diagnostic tool as well as a curative method has not been clearly established in contemporary practice. The traditional initial approach to an anterior mediastinal mass identified on CT involves attaining histological diagnosis through image directed biopsy. A decision to proceed to thymectomy is usually then undertaken if thymoma is identified on histology. The surgical approach has usually involved resection of the thymus gland in its entirety through median sternotomy.

The need for preoperative histology before VAT thymectomy is debatable. CT alone has 97% sensitivity at distinguishing a thymic mass from other possible differentials.[5] Solaini et al. have reported a diagnostic accuracy of 100% with the use of VAT as a primary diagnostic tool in regard to a mediastinal mass.[6] Attempts at establishing a preoperative diagnosis through percutaneous biopsy have the potential to yield inaccurate results. CTGB is operator dependant and has a sensitivity of between 83.6% and 91.9% and a specificity of 90.3%–100% for both fine-needle aspiration (FNA) as well as tru-cut biopsy.[5],[7],[8] Morrissey et al. described the diagnostic accuracy of FNA to be as low as 77%.[9] These results suggest that preoperative histological confirmation by CTGB is an unnecessary step and thus inefficient. CTGB is not without complication. There have been reports of pneumothorax in up to 25% of patients as well as tumour seeding and massive haemothorax.[10],[11] In our series, all patients had some form of thymic enlargement on CT, suspected to be malignant until proven otherwise. In our series, there were no cases of prolonged pneumothorax, major haemorrhage or other surgical complications suggesting that a VATS approach is as safe as CTGB.

Median sternotomy with complete thymus excision has historically been the gold standard in regard to the surgical approach. The VATS approach has been gradually gaining more popularity and frequency in use. There have been multiple published case reports and case series on the use of a VAT approach in resection of thymoma. The experience of individual cases thus far has been favourable, and none have highlighted an increase in operative complication rate, early morbidity or recurrence rate in regard to VAT thymectomy.[12],[13] These results are in accordance with our series. Although there were 6 patients with R1 resection on final histology, there were no cases of tumour recurrence on median follow-up of 5.6 years.

There is controversy regarding the optimal approach for VATS thymectomy, that is, right versus left-sided approach. It is argued that it is technically easier to dissect the left inferior horn of the thymus and the aortopulmonary window to remove ectopic thymic tissue through a left-sided approach. It can however be argued that this may only be relevant in patients with MG as patients with non-MG thymoma need microscopic tumour clearance. A right-sided approach allows for better visualisation of the superior vena cava and innominate vein and is ergonomically easier for right-handed surgeons to resect the thymus from the inferior horns moving up superiorly. In our series, we have safely utilised a right-sided approach in all of our patients with good oncological results. As there is no clear evidence for superiority between left- and right-sided approach, an approach in which a surgeon feels most comfortable and achieves low morbidity, mortality and good oncological clearance should be used.

Lin et al. found that VAT patients had a significantly shorted LOS when compared to the sternotomy approach (5.6 days vs. 8.1 days).[14] The LOS for their sternotomy group is almost double our series. We suspect this is most likely due to reduced pain associated with a VAT approach when compared to sternotomy. Reduced pain is associated with improved functional outcome during the recovery period and thus earlier discharge.[15] In addition, median sternotomy is associated with a both deep sternal wound infection and osteomyelitis. A VAT approach eliminates the risk of osteomyelitis, sternal breakdown and possible re-wiring and/or reconstruction.

There is no clear guidance in literature regarding the use of VAT thymectomy in regards to long-term oncological efficacy. Although there are multiple studies addressing the use of VAT thymectomy in treating myasthenia patients, our patient group underwent thymectomy specifically for thymic enlargement and suspected malignancy. A review article by Davenport and Malthaner recommend that the VAT approach should only be used in Stage I thymoma.[16] Odaka et al. have reported their single centre experience with 62 VAT thymectomy patients for thymoma with acceptable oncological outcomes for Stage I and Stage II thymoma (5-year disease-free survival of 100% and 96.1%, respectively).[17] Maggi et al. have reported no difference in recurrence rates between VAT and sternotomy approach in a single centre study of myasthenia associated thymoma with follow-up of 20 years.[18] However, Kimura et al. have reported thymoma recurrence rate of 6.7% in their retrospective review of 45 VAT thymectomy patients, although their study lacked clear data regarding histopathological grading and whether or not those with R1 resection went on to receive adjuvant therapy.[19]

Some papers have shown that patients with incomplete resection can achieve an overall survival comparable to those with complete resection, while others have shown that incomplete resection is associated with increased recurrence and worsening survival.[20],[21],[22] Defining R1 resections in thymoma can be problematic when the tumour extends to the edge of the capsule as there is no anatomical free margin. This may suggest that R1 resection has little prognostic significance.

Re-resection and adjuvant treatment may prolong survival in patients with recurrence and long-term survival in these patients can be favourable due to thymomas slow-growing nature. This highlights the importance of long-term follow-up and early detection in recurrence of disease. We have utilised the VATS approach in Stage I–III thymoma with no cases of recurrence or re-operation in 5 years follow-up. Although 7 patients had R1 resection, they were referred postoperatively for radiotherapy. We suspect this may have contributed to disease-free outcomes; however, the exact role of radiotherapy following incomplete thymoma resection is still equivocal.[23] Further studies with a larger sample size are needed to attain definitive conclusions in this regard.

 ¤ Conclusion Top

Patients with a suspicious anterior mediastinal mass do not require CT-guided biopsy as it is an unnecessary step. These patients should be referred to a thoracic surgeon with experience in VAT thymectomy and discussed at a multidisciplinary team meeting. The study demonstrates that VAT thymectomy is an acceptable first-line approach towards the suspicious anterior mediastinal mass and should be the gold standard as it is safe, efficient and provides good oncological outcomes at 5 years follow-up.

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Conflicts of interest

There are no conflicts of interest.

 ¤ References Top

Engels EA, Pfeiffer RM. Malignant thymoma in the United States: Demographic patterns in incidence and associations with subsequent malignancies. Int J Cancer 2003;105:546-51.  Back to cited text no. 1
Drachman DB. Myasthenia gravis. N Engl J Med 1994;330:1797-810.  Back to cited text no. 2
Sugarbaker DJ. Thoracoscopy in the management of anterior mediastinal masses. Ann Thorac Surg 1993;56:653-6.  Back to cited text no. 3
Ye B, Tantai JC, Ge XX, Li W, Feng J, Cheng M, et al. Surgical techniques for early-stage thymoma: Video-assisted thoracoscopic thymectomy versus transsternal thymectomy. J Thorac Cardiovasc Surg 2014;147:1599-603.  Back to cited text no. 4
Yonemori K, Tsuta K, Tateishi U, Uno H, Asamura H, Matsuno Y, et al. Diagnostic accuracy of CT-guided percutaneous cutting needle biopsy for thymic tumours. Clin Radiol 2006;61:771-5.  Back to cited text no. 5
Solaini L, Bagioni P, Campanini A, Poddie BD. Diagnostic role of videothoracoscopy in mediastinal diseases. Eur J Cardiothorac Surg 1998;13:491-3.  Back to cited text no. 6
Priola AM, Priola SM, Cataldi A, Ferrero B, Garofalo G, Errico L, et al. CT-guided percutaneous transthoracic biopsy in the diagnosis of mediastinal masses: Evaluation of 73 procedures. Radiol Med 2008;113:3-15.  Back to cited text no. 7
Greif J, Staroselsky AN, Gernjac M, Schwarz Y, Marmur S, Perlsman M, et al. Percutaneous core needle biopsy in the diagnosis of mediastinal tumors. Lung Cancer 1999;25:169-73.  Back to cited text no. 8
Morrissey B, Adams H, Gibbs AR, Crane MD. Percutaneous needle biopsy of the mediastinum: Review of 94 procedures. Thorax 1993;48:632-7.  Back to cited text no. 9
Matsumoto K, Ashizawa K, Tagawa T, Nagayasu T. Chest wall implantation of thymic cancer after computed tomography-guided core needle biopsy. Eur J Cardiothorac Surg 2007;32:171-3.  Back to cited text no. 10
Yaacob Y, Muda S, Zakaria R. Fatal mediastinal biopsy: How interventional radiology saves the day. Ann Thorac Med 2012;7:107-9.  Back to cited text no. 11
  [Full text]  
Limmer KK, Kernstine KH. Minimally invasive and robotic-assisted thymus resection. Thorac Surg Clin 2011;21:69-83, vii.  Back to cited text no. 12
Pennathur A, Qureshi I, Schuchert MJ, Dhupar R, Ferson PF, Gooding WE, et al. Comparison of surgical techniques for early-stage thymoma: Feasibility of minimally invasive thymectomy and comparison with open resection. J Thorac Cardiovasc Surg 2011;141:694-701.  Back to cited text no. 13
Lin MW, Chang YL, Huang PM, Lee YC. Thymectomy for non-thymomatous myasthenia gravis: A comparison of surgical methods and analysis of prognostic factors. Eur J Cardiothorac Surg 2010;37:7-12.  Back to cited text no. 14
Chetty GK, Khan OA, Onyeaka CV, Ahmad F, Rajesh PB, Waller DA. Experience with video-assisted surgery for suspected mediastinal tumours. Eur J Surg Oncol 2004;30:776-80.  Back to cited text no. 15
Davenport E, Malthaner RA. The role of surgery in the management of thymoma: A systematic review. Ann Thorac Surg 2008;86:673-84.  Back to cited text no. 16
Odaka M, Akiba T, Mori S, Asano H, Marushima H, Yamashita M, et al. Oncological outcomes of thoracoscopic thymectomy for the treatment of stages I-III thymomas. Interact Cardiovasc Thorac Surg 2013;17:285-90.  Back to cited text no. 17
Maggi L, Andreetta F, Antozzi C, Baggi F, Bernasconi P, Cavalcante P, et al. Thymoma-associated myasthenia gravis: Outcome, clinical and pathological correlations in 197 patients on a 20-year experience. J Neuroimmunol 2008;201-202:237-44.  Back to cited text no. 18
Kimura T, Inoue M, Kadota Y, Shiono H, Shintani Y, Nakagiri T, et al. The oncological feasibility and limitations of video-assisted thoracoscopic thymectomy for early-stage thymomas. Eur J Cardiothorac Surg 2013;44:e214-8.  Back to cited text no. 19
Ruffini E, Detterbeck F, Van Raemdonck D, Rocco G, Thomas P, Weder W, et al. Tumours of the thymus: A cohort study of prognostic factors from the European Society of Thoracic Surgeons database. Eur J Cardiothorac Surg 2014;46:361-8.  Back to cited text no. 20
Venuta F, Rendina EA, Klepetko W, Rocco G. Surgical management of stage III thymic tumors. Thorac Surg Clin 2011;21:85-91, vii.  Back to cited text no. 21
Attaran S, McCormack D, Pilling J, Harrison-Phipps K. Which stages of thymoma benefit from adjuvant chemotherapy post-thymectomy? Interact Cardiovasc Thorac Surg 2012;15:273-5.  Back to cited text no. 22
Hamaji M, Omasa M, Chen F, Yamada T, Sato M, Menju T, et al. Survival and treatments in patients with incompletely resected thymoma. Asian Cardiovasc Thorac Ann 2014;22:712-8.  Back to cited text no. 23


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