Role of Endobronchial Ultrasound Guided real time Transbronchial Needle Aspiration in Mediastinal Lymphadenopathy: A Case Series

Original Article

Role of Endobronchial Ultrasound Guided real time Transbronchial Needle Aspiration in Mediastinal Lymphadenopathy: A Case Series

Avinash Peddi ¹, Sridhar.R ¹ and Narasimhan.R ²

¹DNB Post Graduate, Department of Respiratory Medicine, Apollo Main Hospital, Chennai.
²Senior Consultant, Department of Respiratory Medicine, Apollo Main Hospital, Chennai.

Corresponding Author: Dr. Avinash Peddi, DNB post graduate, Department of Respiratory Medicine.
Email: dr.sridhar.ily@gmail.com.

Mediastinal lymphadenopathy is expected to be the common mediastinal masses because this is caused by high prevalent disease like tuberculosis, lung cancer metastasis, lymphoma and sarcoidosis etc; especially in very high tuberculosis prevalent country like India. Mediastinal lymph node enlargement is most often due to lymphoma ², metastatic cancer ¹, granulomatous inflammation such as that caused by sarcoidosis or infection. Infection should be considered when the adenopathy is associated with a pulmonary opacity. Tuberculosis is a notable cause of mediastinal adenopathy that can mimic sarcoidosis or malignancy and should be suspected in a host with known tuberculosis risk factors, such as recent known exposure or residence in an endemic area ³.

Fungal infections that cause granulomas, particularly histoplasmosis, may present with mediastinal and hilar adenopathy in the absence of a pulmonary opacity ⁴. Numerous less common causes of mediastinal adenopathy are described, including Castleman’s disease or angiofollicular lymphoid hyperplasia.

Tuberculous lymphadenitis is another important consideration for middle mediastinal mass. Tuberculosis (TB) is responsible for up to 43% of all of peripheral lymphadenopathy in the developing world. Total estimated incidence of tuberculous lymphadenopathy was 30.8 per 100 000 population in India. The cervical region is most frequently involved, but mediastinal involvement occurs in approximately 27% of cases ⁵.

For evaluation of mediastinal adenopathy or other lesions in the middle mediastinum, transbronchial needle aspiration (TBNA) via the fiberoptic bronchoscope offers a less invasive option to surgical mediastinoscopy ^6-8. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a recent technology that has significantly improved the ability of pulmonologists to diagnose and stage non–small cell lung cancer in a minimally invasive manner. With the advent of a curvilinear ultrasound probe integrated at the end of the bronchoscope, TBNA with a 22-gauge needle can be performed under real-time ultrasonographic guidance ^9-11. Endoscopic biopsies are generally preferred nowadays in view of lesser complications and ease compared to surgical interventions.

Objective To know the effectiveness of real‐time EBUS in the evaluation of mediastinal lymphadenopathy.

In our study 50 cases of mediastinal lymphadenopathy diagnosed by CT scan chest which referred for EBUS-TBNA to department of respiratory medicine, Apollo main hospitals, Chennai were included after obtaining the informed consent. All these patients were subjected to EBUS guided TBNA under general anaesthesia and localized the enlarged mediastinal node in station 4R, 7 or 10 and then EBUS guided real time TBNA of mediastinal nodes was done. TBNA Specimens were sent for histopathological examinations and reports were collocated and analyzed.

In our study 50 patient with mediastinal lymphadenopathy on CT chest was included among these 30 were males and 20 were females with Male to female ratio of 3:1. Mean age group in our study was 50 years with age range from 22 to 75 years.

Among 50 cases of mediastinal lymphadenopathy, arrived diagnosis in EBUS TBNA in 42 cases and in other 8 cases inconclusive results. Pathological reports of EBUS TBNA sample were listed in following table:1.

Table:1 Pathological reports of EBUS TBNA specimens.

In our study population, final diagnosis of mediastinal lymphadenopathies were tuberculosis in 17 cases[34%], malignancy in 16 cases[32%], sarcoidosis in 8 cases[16%], sub acute inflammation in 1 case[2%] and non diagnostic in 8 cases[16%].

Table: 2 Final diagnosis of mediastinal lymphadenopathy

Endobronchial ultrasound – guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive technique allowing sampling of mediastinal lymph nodes via fine needle aspiration under direct sonographic visualisation. It has a low rate of morbidity, and has demonstrated utility in the diagnosis of mediastinal lymphadenopathy secondary to malignancy, lymphoma and sarcoidosis.

In Tremblay A et al randomized controlled trial of 50 patients with clinically suspected sarcoidosis due to the presence of mediastinal and hilar adenopathy, the diagnostic yield of EBUS TBNA was superior to blind TBNA, with a sensitivity of 83% and specificity of 100% 12 . In another study Gupta et al randomized control study in 130 patient of sarcoidosis, also stated that the diagnostic yield of EBUS TBNA was superior to blind TBNA ¹³. In study by Herth FJF et al stated that EBUS-TBNA is a promising new method for sampling mediastinal lymph nodes ¹⁴. It appears to permit more and smaller nodes to be sampled than conventional TBNA, and it is safe. In our study we preferred EBUS TBNA over blind TBNA in all our mediastinal lymphadenopathy and the diagnostic yield of EBUS TBNA was 84% in our study.

EBUS with real-time needle aspiration has shown itself to be extremely useful in assessing nodular metastases. In three of the studies reviewed 15,16,17, imaging techniques, fundamentally CT and FDG-PET, which are frequently used as initial staging methods, displayed a lower sensitivity and specificity than that observed for EBUS–TBNA. Unlike imaging techniques, EBUS– TBNA enables the identification and sampling of lymph nodes ≤1 cm in size.

The sensitivity of real-time EBUS–TBNA for assessment of mediastinal and hilar metastasis seems to be equivalent or even superior to that of mediastinoscopy, the reference technique currently used to assess nodular metastases. According to the results of a recent pooled analysis, the sensitivity of mediastinoscopy ranges from 72–89% 18. EBUS– TBNA could replace mediastinoscopy in an important percentage of cases, though, due to the low NPV observed in some studies, surgical techniques cannot be ruled out in negative cases.

The main limitation of EBUS–TBNA is its inability to visualise posterior nodes (stations 5, 7, 8 and 9) ¹⁵. EUS–FNA is a complementary technique that enables visualisation of posterior nodes not visualised by EBUS–TBNA but does not allow the visualisation of the anterior mediastinum ^15,16

While the efficacy of EBUS-TBNA is now firmly established in the evaluation of lung cancer, there is also an increasing role for the initial evaluation of isolated mediastinal adenopathy due to other conditions such as sarcoidosis, tuberculosis etc. In our study group, EBUS TBNA showed granuloma in 25 cases. Among these granulomatous lymphadenitis based on additional pathological features like caseating necorsis, presence of AFB and clinicoradiological features along with mantoux test results which was non reactive in sarcoidosis patients.

In a prospective trial by Navani N et al of 77 patients with isolated mediastinal adenopathy, a specific diagnosis of sarcoidosis, tuberculosis, lymphoma, or other malignancy was made in 67 of them, thus obviating the need for a more invasive surgical mediastinoscopy¹⁹. In our study population, diagnosed malignant mediastinal lymphadenopathy in 16 [32%] cases and also diagnosed mediastinal lymphadenopathy due to tuberculosis in 17 cases [34%] and sarcoidosis in 8 cases [16%]. EBUS technique is helpful in evaluating mediastinal lymphadenopathy which are difficult to approach by image guided percutaneous techniques.

Mediastinal lymphadenopathies are difficult to biopsy since they are nearer to major vessels and airways and located commonly in the middle compartment. Hence mediastinal lymphadenopathy is under represented in many studies since unable to obtain tissue diagnosis. Before the advent of EBUS, Percutaneous transthoracic needle biopsy/FNAC (under CT or ultrasound guidance) or surgical procedures [VATS or Mediastinoscopy] were considered as the initial method of choice in evaluation of mediastinal lesions. EBUS techniques has demonstrated utility in the diagnosis of mediastinal lymphadenopathy secondary to malignancy, tuberculosis and sarcoidosis and easier and lesser complication than more invasive procedures like VATS or mediastinoscopy.

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