Mediastinal staging--the role of endobronchial and endo-oesophageaL sonographic guided needle aspiration

Endoscopic ultrasound in the diagnosis of mediastinal diseases

EUS is a useful tool for diagnosis of mediastinal diseases. EUS-FNA plays an important role in staging of lung cancer and in tissue acquisition in patients with mediastinal masses. In this review, the following issues will be addressed: EUS-FNA and EBUS-TBNA, metastatic mediastinal lymph nodes diagnosed by EUS, EUS in assessment of mediastinal lymph node status for staging of lung cancer, mediastinal lymphoma diagnosed by EUS, sarcoidosis and tuberculosis diagnosed by EUS.

Evolving role of interventional pulmonology in the interdisciplinary approach to the staging and management of lung cancer: bronchoscopic mediastinal staging of lung cancer

Mediastinal lymph node involvement is present in 26%-38% of patients with non-small-cell lung cancer at the time of diagnosis, and it is often the most significant factor in determining surgical resectability. Complete and accurate mediastinal staging of lung cancer is essential for determining prognosis and for guiding optimal treatment strategies. Computed tomography and positron emission tomography are the most widely used noninvasive means for mediastinal staging in lung cancer. However, based on their reported specificities, computed tomography and positron emission tomography findings should be verified by cytohistologic sampling. In recent decades, the technique of transbronchial needle aspiration (TBNA) has been developed, permitting the bronchoscopist to obtain cytohistologic material from the hilar and mediastinal lymph nodes adjacent to the tracheobronchial wall. The technique of TBNA has a great specificity, is safe and cost-effective compared with surgical methods, and can be performed during the initial diagnostic bronchoscopy. Transbronchial needle aspiration sensitivity is 76%-78% but is highly influenced by several factors. Endobronchial ultrasound has been proposed as a means for improving TBNA sensitivity. Recently, a new type of bronchoscope with a built-in convex ultrasound probe directly attached to the tip has been developed to guide TBNA under real-time imaging. Reports on this innovative technique reveal a sensitivity of 94%-95.7%, which is superior to the reported sensitivity of surgical methods. However, ultrasound-guided TBNA and traditional TBNA should be considered complementary techniques, because their integration is likely to become the optimal staging strategy for patients with lung cancer.

Endobronchial ultrasound-guided fine-needle aspiration and liquid-based thin-layer cytology

BACKGROUND

Optimal management of patients with lung cancer requires accurate cell typing of tumours and staging at the time of diagnosis. Endobronchial ultrasound-guided lymph node aspiration as a method of diagnosing and staging lung cancer is a relatively new technique.

AIM

To report the use of liquid-based-thin-layer cytology for the processing and reporting of these specimens.

METHODS

The specimens obtained from 80 patients were processed using the ThinPrep system, with the remainder of the samples being processed as a cell block.

RESULTS

40 of the 81 procedures yielded malignant cells (30 non-small cell carcinoma, 8 small-cell carcinoma and 2 combined small-cell carcinoma/non-small-cell carcinoma). The cell blocks were found to contain sufficient material to allow the immunohistochemical characterisation of tumour cells with a range of antibodies.

CONCLUSION

The use of liquid-based-thin-layer cytological techniques provides high-quality specimens for diagnostic purposes. When used in conjunction with cell blocks, sufficient material may be obtained to allow immunohistochemical studies to confirm the tumour cell type. Given the current move towards centralisation of pathology services, this approach gives the pathologist high-quality specimens without the need for direct onsite support at the time of the procedure.