Retrosternal Thyroid Research Articles

Asymptomatic retrosternal thyroid goitres: when is surgical management appropriate?

Asymptomatic retrosternal thyroid goitres: when is surgical management appropriate?

Huge Nodular Goitre with Retrosternal Extension- A Rare Case Report

Retrosternal goitre is very rare condition which account for to of thyroidectomy patients Though rare it can be better managed surgically In this article we report a rare case of year old female who had nodular goiter with huge retrosternal extension associated with hyperthyroidism Majority of retrosternal thyroid can be removed safely by conventional cervical approach Our patient had around cm mass which was impossible to remove it from conventional approach and hence total thyroidectomy by a combined cervical sternotomy approach Procedure was uneventful and patient is doing fine in months of follow up The role of thyroidectomy in patients with retrosternal goitre provides yet another area of surgical controversy

Transvaginal Probe Application in the Visualization and Evaluation of a Retrosternal Thyroid Mass

Ultrasound evaluation of the thyroid gland is relatively easy in most cases with excellent visualization of the gland with linear transducer allowing clear characterization of lesions as well as guidance for biopsy. However when retrosternal thyroid tissue extension is present, evaluation may be difficult. We report the simple use of widely available transvaginal probe in helping to visualize and evaluate the retrosternal thyroid tissue.

A Rare Case of Huge Retrosternal Goitre Managed by Total Thyroidectomy with Medial Sternotomy

Retrosternal goitre is very rare condition which account for 5 to 20 % of thyroidectomy patients. Though rare, it can be better managed surgically. In this article we report a rare case of 60 year old female who had nodular goiter with huge retrosternal extension. Majority of retrosternal thyroid can be removed safely by conventional cervical approach. Our patient had around 20 x 18 x 6 cm mass which was impossible to remove it from conventional approach and hence total thyroidectomy with medial sternotomy was done. Procedure was uneventful and patient is doing fine in of follow-up. The role of thyroidectomy in patients with retrosternal goitre provides yet another area of surgical controversy I. Introduction Retrosternal goiter is defined when 50 % of the thyroid is below the thoracic inlet. This can also be called as intrathoracic goiter. Retrosternal goiter is a very rare condition which account for 5 to 20 % of thyroidectomy patients. Mediastinal extension is more common in huge goiters with a peak incidence in 5th to 6th decade. This is usually rare when the patient has associated hyperthyroidism which may increase the risk of complications. The reported incidence of goiters with thyroid malignancy is around 3 to 17 %. Retrosternal goitre occurs when the thyroid enlarges downwards into the chest. Although the great majority of retrosternal goitres are extensions from the neck, pure intrathoracic goitres are very rare. Any goitre that descends below the plane of thoracic inlet and growing into the anterior mediastinum for > 2cms.

Retrosternal Goiter: 30-Day Morbidity and Mortality in the Transcervical and Transthoracic Approaches.

Retrosternal goiters pose a significant challenge in determining the indications and appropriate approach for surgical removal while limiting postoperative morbidity and mortality. The objective of this study is to use the National Surgical Quality Improvement Program (NSQIP) database to compare outcomes of transcervical and transthoracic approaches for retrosternal goiter removal and to review the literature regarding the varying indications for the 2 surgical approaches. Administrative database analysis. NSQIP database. The NSQIP database was queried for all cases of retrosternal thyroid: 2716 patients were included, which represents one of the largest data reviews of patients with retrosternal thyroid pathology who underwent surgery. Data were analyzed to examine morbidity and mortality of the cervical and transthoracic approaches. Patient demographics and preoperative comorbidities were similar between groups. Patients undergoing a transthoracic approach experienced increased rates of unplanned intubations and need for transfusion and length of stay postoperatively. A transthoracic approach is associated with increased rates of several critical postoperative morbidities, and the data indicate the potential of increased overall mortality. Given equivalent retrosternal extension, a transcervical approach should be attempted whenever anatomically possible, regardless of pathology.

Establishment of an endobronchial ultrasound-guided transbronchial fine needle aspiration service with rapid on-site evaluation: 2 years experience of a single UK centre.

Endobronchial ultrasound (EBUS)-guided transbronchial fine needle aspiration (TBFNA) is now well established as a minimally invasive, effective investigation which can provide information on both diagnosis and stage of lung cancer and is also useful in the investigation of mediastinal lymphadenopathy of uncertain aetiology. The service can be provided with or without rapid on-site evaluation (ROSE) for specimen triage and provisional diagnosis. We outline our experience from the first 2 years of providing an EBUS service with ROSE, highlighting the practicalities of service provision, pitfalls encountered and lessons learned. Aspirates from all EBUS procedures performed during the first 2 years of our service from 16 October 2012 to 15 October 2014 are included. We describe the activities undertaken prior to each EBUS list, the EBUS TBFNA procedure, specimen handling and procedure for ROSE. A total of 591 aspirates were performed from 352 patients, including 573 (97%) lymph node aspirates, 17 (2.9%) lung mass samples and one aspirate from a retrosternal thyroid cyst (0.1%). There were 498 (84.1%) adequate samples at ROSE, 82 (13.9%) inadequate, one (0.2%) abandoned and 11 (1.9%) where ROSE was not performed. Four hundred and seventy (79.5%) samples showed concordance between the ROSE and final diagnoses. No adequate samples were obtained for 11 patients (3.1%) after final cytological analysis, resulting in a final adequacy rate of 96.9%. In our experience, ROSE provides a clear advantage in providing a patient-centred EBUS service by facilitating specimen triage, ensuring adequate sampling and providing a rapid provisional diagnosis, however, there is a learning curve for both the clinicians and cytopathologists involved.

A clinicopathological study of mediastinal masses operated in a tertiary care hospital in Eastern India in 3 years with special reference to thymoma.

The mediastinum is the central portion of the thoracic cavity, limited by pleural cavities laterally, thoracic inlet superiorly, and the diaphragm inferiorly. Housing numerous organs, it is a veritable Pandora's box, within which various lesions may develop. This study was conducted to assess the epidemiologic profile, clinicoradiological features, cytological, and histopathological findings in patients presenting with mediastinal masses in a tertiary care hospital over a period of 3 years. This is a retrospective study of cases presenting with mediastinal masses attending the Cardiothoracic Surgery Department of Medical College, Kolkata between May 2011 and April 2014. Detailed history, physical, and radiological findings were noted. Fine needle aspiration cytology (FNAC) was performed when feasible. Following surgery, histopathological, and immunohistochemical (IHC) examinations of the specimens were undertaken. Of the 22 cases included in our study, ten were anterior, seven middle, and five posterior mediastinal masses. Fifteen cases were male and seven were female. Thymic pathology was detected in seven cases, lymphoma in five, extragonadal germ cell tumor (GCT) in three, schwannoma and pericardial cyst in two cases each and neurofibroma, ganglioneuroma, and retrosternal thyroid in one case each. The age group of the patients for each diagnostic category was found to be of significance. FNAC was done in 15 cases. IHC was required for classification of lymphoma cases (CD45, CD15, CD30, CD20, CD3, Tdt, CD34, and Ki-67). This study reflects the incidence of different mediastinal masses in West Bengal with their clinicopathologic correlation.

Ten-year Comparison of the Prevalence of Thyroid Cancer in the Neck With Retrosternal Thyroid in Shahid Beheshti and Ayatollah Rouhani Hospitals in Babol, Iran

Background: Any deviation in the normal descent of the thyroid gland can lead to ectopic thyroid. In this study ten-year comparison of the prevalence of cervical thyroid cancer with retrosternal thyroid was performed. Objectives: By knowing prevalence of the disease actions may be performed to know the risk factors associated with the disease. The purpose of this study was to compare the prevalence of cervical thyroid cancer with retrosternal thyroid in Shahid Beheshti and Ayatollah Rouhani Hospitals in Babol, Iran, during 2000 - 2010. Materials and Methods: This cross-sectional study was performed on 158 patients referred to Shahid Beheshti and Ayatollah Rouhani Hospitals in Babol City, Iran, during 10 years (from 2000 - 2010). Demographic characteristics, smoking, family history of thyroid cancer, the signs and symptoms and pathology reports were collected in a checklist format. Results: From a total of 158 patients with thyroid cancer, 144 cases were diagnosed with cervical thyroid and 14 cases diagnosed with retrosternal thyroid. In both groups, dyspnea and hoarseness were the most prevalent symptoms. The pathology report showed that in the cervical thyroid, benign cases were more than malignant cases but in retrosternal thyroid, the opposite happened. Conclusions: The prevalence of cervical thyroid was 91.1% and the prevalence of retrosternal thyroid was about 8.9%. The prevalence rates of malignancy in the cervical and retrosternal thyroid were 34.7% and 21.4%, respectively.

Retrosternal Thyroid Goiter: Recurrent Laryngeal Nerve Dissection According to the Charles Proye's Toboggan Technique

Introduction: We present a case report supported by a video of a case of recurrent retrosternal thyroid goiter with superior identification of the recurrent laryngeal nerve (also called the Charles Proye's toboggan technique).1 Materials and Methods: In November 2012, we operated a 71-year-old patient for a recurrent unilateral retrosternal thyroid goiter. The patient underwent a subtotal thyroidectomy 20 years earlier; she showed symptoms of airway and esophageal compression. After a CT scan and a laryngoscopy, the patient underwent a right thyroid lobectomy. The surgery of retrosternal goiter is at increased risk for iatrogenic recurrent laryngeal nerve lesion.2 Charles Proye described a surgical technique to avoid this lesion. To have a better exposition, a section of the prethyroid muscles can be considered, particularly if it is a voluminous and/or recurrent goiter.3–4 The approach starts with the thyroid isthmus liberation that is dissected free from the anterior part of the trachea and transected. Then, the middle thyroid vein is divided and the superior pole vessels are divided. The superior pole is then mobilized laterally, and the recurrent laryngeal nerve is searched for at its entry point into the larynx. The nerve function can be verified by the neuromonitoring, which also helps to find it in this vessel-rich area. The dissection continues between the nerve and the posterior part of the thyroid, progressively from top to bottom, descending as on a toboggan. After the recurrent nerve dissection, the goiter can usually be extracted without difficulty, dividing the last vessels holding the goiter inside.1–4 Results: With the toboggan technique, it is often possible to do the thyroidectomy for mediastinal goiter without sternotomy and recurrent nerve damage.1 Using this technique, the recurrent nerve is never put under tension. The patient operated with this technique had a duration of hospitalization of 3 days without any postoperative complication. Conclusions: Whenever possible, we prefer to operate intrathoracic goiters using this technique because it allows us to better recognize and preserve the recurrent nerve without putting it under tension. The Source of Work or Study: In 1981, Charles Proye described a new surgical technique to operate intrathoracic goiters without sternotomy and with preservation of recurrent nerve; the surgery of mediastinal goiter is at increased risk for iatrogenic recurrent laryngeal nerve lesion. We utilize in our clinic this technique for intrathoracic goiters. This video describes the details of the Charles Proye's technique. The authors have not received any payment or support. The article is based on a videocommunication during the congress of the IAES in Helsinki, August 2013. Running time of video: 4 mins, 53 secs

Transoral endoscopic thyroidectomy with central neck dissection: experimental studies on human cadavers

Background With the development of natural orifice trans-luminal endoscopic surgery, studies on transoral video-assisted thyroidectomy in preclinical experiments (e.g., human anatomy and animal trials) were progressing gradually. From 2009 to 2011, embalmed human cadavers were dissected to define the anatomical location, surgical planes, and related neural and vascular structures to create a safe transoral access to the front cervical spaces. Recently, experimental transoral endoscopic thyroidectomy was performed to verify the feasibility of this approach on 15 fresh specimens. Methods Fifteen specimens were placed in the supine position with slight neck extension. Endoscopic incision was made on the midline between the Wharton's duct papillae and two other incisions were made on mandibular first premolar buccal mucosa. Sublingual combined bilateral vestibular tunnels were created from oral cavity to the cervical region. The neck subplatysmal working space was insufflated with CO2 at 6–8 mmHg. The bilateral thyroid lobes and central lymph nodes were dissected under craniocaudal view. Results Three incisions were made in the oral cavity without any incisions on the body surfaces. The distance from the oral cavity to front neck region was the shortest. Bilateral thyroid lobes and central neck region were fully resected via transoral approach. This approach provided a craniocaudal view, in which retrosternal thyroid gland and lymph nodes were easily accessible. The recurrent laryngeal nerve could be identified safely on the inferior cornu of the thyroid cartilage. The only structure at risk was the mental nerve. Camera motion was somewhat limited by the maxillary dentition. The volume of harvested thyroid nodule through sublingual tunnel in the fifteen human cadavers was (40±15) cm3. Conclusion The transoral procedure is progressive and innovative which not only gives the best cosmetic result and minimal access trauma but also provides a craniocaudal view.

Low-Activity 124I-PET/Low-Dose CT Versus 99mTc-Pertechnetate Planar Scintigraphy or 99mTc-Pertechnetate Single-Photon Emission Computed Tomography of the Thyroid

The standard thyroid functional imaging method, 99mTc-pertechnetate (99mTc-PT) planar scintigraphy, has technical drawbacks decreasing its sensitivity in detecting nodules or anatomical pathology. 124I-PET, lacking these disadvantages and allowing simultaneous CT, may have greater sensitivity for these purposes. We performed a blinded pilot comparison of 124I-PET(/CT) versus 99mTc-PT planar scintigraphy or its cross-sectional enhancement, 99mTc-PT single-photon emission CT (SPECT), in characterizing the thyroid gland with benign disease. Twenty-one consecutive adults with goiter underwent low-activity (1 MBq/0.027 mCi) 124I-PET/low-dose (30 mAs) CT, 99mTc-PT planar scintigraphy, and 99mTc-PT-SPECT. Endpoints included the numbers of “hot spots” with/without central photopenia and “cold spots” detected, the proportion of these lesions with morphological correlates, the mean volume and diameter of visualized nodules, and the number of cases of lobus pyramidalis or retrosternal thyroid tissue identified. 124I-PET detected significantly more “hot spots” with/without central photopenia (P < 0.001), significantly more nodules (P < 0.001), and more “cold spots” than did 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT, including all lesions seen on the 99mTc-PT modalities. Ultrasonographic correlates were found for all nodules visualized on all 3 modalities and 92.5% of nodules seen only on 124I-PET. Nodules discernible only on 124I-PET had significantly smaller mean volume or diameter (P < 0.001) than did those visualized on 99mTc-PT planar scintigraphy or 99mTc-PT-SPECT. 124I-PET(/CT) identified significantly more patients with a lobus pyramidalis (P < 0.001) or retrosternal thyroid tissue (P < 0.05). 124I-PET(/CT) may provide superior imaging of benign thyroid disease compared to planar or cross-sectional 99mTc-PT scintigraphy.

Endobronchial Ultrasonography with Transbronchial Needle Aspiration to Sample a Solitary Substernal Thyroid Nodule: A New Approach

Sampling of solitary thyroid nodules (STNs) is a common procedure performed for cytological diagnosis. The easiest and safest method is ultrasound guided fine needle aspiration biopsy (US-FNAB). This technique is usually performed under local anaesthesia in an office setting. In contrast, sampling a substernal STN could prove to be more difficult and problematic, and sometimes requires more invasive procedures. We describe a case of substernal thyroid nodule, where malignancy was excluded using endobronchial ultrasonography with transbronchial fine needle aspiration (EBUS-TBNA). We emphasise the feasibility and safety of EBUS-TBNA in sampling retrosternal thyroid nodules. In appropriate settings, this procedure can help avoid more invasive testing, and subsequently decrease the cost and complications.

Remnant Large Retrosternal Thyroid Goiter after Thyroidectomy

Remnant Large Retrosternal Thyroid Goiter after Thyroidectomy

Definition of retrosternal thyroid growth

The diagnosis of a retrosternal thyroid growth (RTG) causes extended surgical exploration and a different surgical treatment planning (partial sternotomy, thoracotomy) and is usually made by the help of thyroid scintigraphy and ultrasonography. But both examinations have problems in determining the retrosternal thyroid extend in the complex anatomy of sternal bone and often pathologically altered manubrioclavicular joints (MCJ). This study evaluates the variation of anatomical structures in the upper sternal region, the position of the sternal markers during scintigraphy, and the frequency of enhanced bone metabolism of the MCJs. For this aim, the positions of the upper edges of the MCJs were measured by X-ray fluoroscopy in 50 consecutive patients. To prove the exactness of an external marker as used in thyroid scintigraphy, the variation of the marker position was also determined. The activity in the MCJs was measured semiquantitatively with bone scintigraphy in further 100 patients (mean age: 62.3 yrs, SD: 14.2 yrs). As results, the upper edges of the medial clavicular edges exceed the upper margin of the sternal edge up to 2.7 cm. The distance between the medial clavicular edges ranged from 2.3 - 5.6 cm. The position of the sternal marker was correct in the horizontal deviation (mean: 0.1 cm, SD: 0.48 cm) but too high in the vertical position (mean: 2.2 cm, SD: 0.67 cm). During bone scintigraphy, the MCJs showed no enhanced activitity in 75/200 joints, medium activity in 96/200 joints, and strong enhanced activity in 29/200 joints. In consequence, a high variability in the position of the anatomical structures has to be considered together with a high amount of degenerative alterations. The position of the sternal marker was inappropriate in the vertical direction and overestimated a possible retrosternal growth.

Equal and opposite expert opinion. Airway obstruction caused by a retrosternal thyroid mass: management and prospective international expert opinion*

Anticipated problems with airway management during anaesthesia require careful planning, particularly when they involve a risk of airway obstruction. Advice may be sought from published literature (usually written by experts) or through direct communication with experts. More frequently, expert involvement is through retrospective review following patient harm. We present the case of a patient suffering from a retrosternal thyroid mass that was compressing her trachea in the midline and dividing it into two 2 × 3 mm lumens. After local discussion the patient underwent thyroidectomy. We invited international experts in anaesthetic airway management to review her case and submit their opinions regarding the best airway management for this difficult case. Opinions differed markedly, mirroring the published literature. Some experts specifically criticised techniques that, unbeknown to them, were proposed by others. The case raises issues about the nature of expert opinion that extends beyond this particular case. The nature and implications of expert opinion, when evidence is absent or conflicting, are discussed.

Microfilariae coexisting with a follicular lesion in thyroid aspirate smears in an uncommon case of a retrosternal thyroid mass, clinically presenting as malignancy

To the Editor, Filarial infection is a public health problem in the tropical regions of South-east Asia, including the Indian subcontinent that includes certain areas of heavy infestation, like Madhya Pradesh, Bihar, Jharkhand, along with others. It is caused by the nematodes Wuchereria bancrofti, Brugia malayi, Brugia tumori and others, transmitted through a mosquito Culex fastigens. Its disease manifestations include lymphoedema and superficial swellings.[1–3] Varied sites of involvement documented on aspirate smears include breast, epididymis, spermatic cord, lungs, etc.[4–6] Over the years, it has been uncommonly identified in the thyroid.[7–13] Herein, we present an uncommon case of a retrosternal thyroid mass that clinically presented as malignancy and on aspiration cytology disclosed a follicular lesion with coexisting microfilariae. A 55-year-old gentleman from Ranchi (Jharkhand, India) was referred to our hospital with complaints of anterior neck swelling since 2 months, associated with dysphagia to solids and alteration of voice for a month. He had been a tobacco chewer for 30 years. He also disclosed history of aspiration a month ago, along with breathlessness. On clinical examination, his general condition was good. On local examination, a soft swelling was noted over his right thyroid and isthmus and a 10×7 cm hard swelling was noted over his left thyroid, extending into the retro sternum that did not move with deglutition. Left vocal cord palsy was noted. There was no stridor. Clinically, he was presumed with a diagnosis of stage IV carcinoma thyroid. He underwent laboratory and radiological investigations, including an outside computed tomography (CT) scan, followed by fine-needle aspiration cytology (FNAC) on three occasions, including twice at our hospital. His hemoglobin was normal i.e. 12 gm/dl (Normal: 13-17 gm/dl). Total leukocyte count was high i.e., 13.7×10e9/L (Normal: 4-10×10e9/L), including absolute neutrophilia. Percentage and absolute eosinophil counts were normal 4.73% and 0.65×10e9/L (Normal: 1-6% and 0.2-1×10e9/L). Basophil percentage was marginally high i.e., 0.33% (Normal: 0-0.2%). His thyroid function tests were within normal limits. There was no access for thyroid scan results. Limited accessible imaging findings included a CT scan report that disclosed a left thyroid lobe lesion, eroding the thyroid cartilage, trachea and thoracic inlet. His chest X-ray was normal. FNAC was performed by multiple passes in the thyroid using a 23-gauge needle. Smears were fixed in alcohol stained with Papanicolaou (Pap), while air-dried smears were stained with Giemsa stain. The initial smears were reported as papillary carcinoma thyroid. Repeat smears were hypercellular, comprising benign appearing follicular cells in focal acinar formations, flat monolayered sheets and focal papillaroid arrangements, lacking anatomical edge. Cells exhibited focal nuclear overlapping, focal grooves and fine chromatin clearing in rare cells. No nuclear elongation, uniform nucleomegaly or intranuclear inclusions were noted within the hypercellular smears. Besides, there were sheets of cystic macrophages and Hurthle cells in a background of thick and thin colloid. Diagnosis of an atypical follicular lesion of undetermined significance was considered. On critical examination, microfilariae of W. bancrofti were identified that displayed presence of sheath and were deficient in somatic nuclei at the posterior end of the body that was curved. A few rhomboid-shaped Charcot Leyden (CL) crystals were noted. There were no inflammatory cells. The previous smears were reviewed and a final diagnosis of microfilarial infestation, along with follicular lesion (of undetermined significance) was offered. [Figure ​[Figure1a1a–e] Figure 1 a) Hypercellular smear showing clusters of follicular cells. Pap stain ×100; b) Follicular cells with surrounding macrophages. Pap stain ×400; c) Cells showing focal nuclear overlapping. Pap stain ×1000; d) Flat monolayered sheet ... Following, the patient succumbed to death within a week. However, post-mortem examination could not be performed.

Many ways to skin a cat. Airway obstruction by a retrosternal thyroid mass: management and international expert opinion

Many ways to skin a cat. Airway obstruction by a retrosternal thyroid mass: management and international expert opinion

Infective complications from endobronchial ultrasound-transbronchial needle aspiration

To the Editors: We read with significant interest the report from Haas 1 in a recent issue of the European Respiratory Journal , which described two cases of infectious complications following endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). This technique has been widely adopted for the evaluation of mediastinal and hilar lesions for several reasons, including its high-diagnostic accuracy, minimally invasive nature and excellent safety profile. As stated by Haas 1, no significant complications have previously been reported. We recently experienced a similar complication in our interventional bronchoscopy centre (Royal Melbourne Hospital, Parkville, Australia). A female with small cell lung cancer and a moderate-sized retrosternal thyroid lesion underwent EBUS-TBNA sampling of the thyroid lesion for the purpose of staging. …

Airway obstruction caused by the systemic inflammatory syndrome associated with trauma and retrosternal goitre

A 71-year-old previously healthy male presented to the emergency department following a high speed motorcycle crash. Computed tomography (CT) of the brain, cervical spine, chest, abdomen and pelvis showed bilateral pulmonary contusion, a left third rib fracture, and an incidental finding of a right-sided retrosternal thyroid mass causing tracheal compression and deviation. He was admitted to the intensive care unit (ICU) because of the pulmonary contusion but was discharged to the ward after 48h.

Experiences on the application of video-assisted mediastinoscopy for 40 patients with mediastinal lesions.

To evaluate the clinical experiences on the application of videoassisted mediastinoscopy for 40 patients with mediastinal lesions. Forty patients underwent video-assisted mediastinoscopy through neck-way surgery, including 17 cases with sole mediastinal nodule or mass, of which the pathologic diagnosis was warranted; 18 cases diagnosed as lung cancer with enlarged mediastinal lymph nodes, of which the clinical stage needed to be clarified; and 5 cases of mediastinal mass with miscellaneous clinical conditions. The results of mediastinoscopy biopsy and pathological diagnosis were analyzed. Satisfied tissue for detailed examination was obtained for all of the 40 cases who underwent mediastinoscopy. The successful rate for biopsy was 100%. The final pathologic diagnosis were 11 cases of lymph node metastasis from lung cancer, 4 cases of lymph node metastasis from unknown site, 9 cases of sarcoidosis, 6 cases of lymph node reactive hyperplasia, 4 cases of tuberculosis, 2 cases of lymphoma, 2 cases of mediastinal cyst, 1 case of retrosternal thyroid, 1 case of inflammatory granuloma. Two cases of postoperative hemorrhage related to surgery were successfully treated. Video-assisted mediastinoscopy is safe and useful. It's essential for the diagnosis of sole mediastinal mass, a good method to clarify the pathologic stage of patients with lung cancer, and the only way to get the pathologic diagnosis for some special mediastinal disease.