Endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of intrathoracic lymph node metastases from extrathoracic malignancies

Abstract

Intrathoracic lymph node enlargement is a common finding in patients with extrathoracic malignancies. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a technique that is commonly used for lung cancer diagnosis and staging but that has not been widely investigated for the diagnosis of enlarged mediastinal and lobar lymph nodes in patients with extrathoracic malignancies. We conducted a retrospective study of 117 patients with extrathoracic malignancies who underwent EBUS-TBNA for diagnosis of intrathoracic lymph node enlargement from October 2005 to December 2009 and compared the EBUS-TBNA findings with the final diagnoses. EBUS-TBNA diagnosed mediastinal metastases in 51 of the 117 (43.6 %) cases and gave an alternate diagnosis or ruled out the presence of malignancy in 35 (56.4 %). Fourteen of these 35 patients underwent further surgical investigation, while the remaining 21 had clinical and radiological follow-up for 18 months. No false negatives were found in the surgery group. In the follow-up group, 13 patients had stable or regressive lymphadenopathy, and eight developed clinicoradiological progression and were assumed to have been false negatives by EBUS-TBNA. The sensitivity and negative predictive value of EBUS-TBNA were 86.4 and 75 %, respectively. Immunohistochemical staining (IHC) was performed in 80.4 % of the samples obtained by EBUS-TBNA. In samples obtained from ten patients with metastatic breast cancer, estrogen receptor expression was successfully assessed in eight patients and progesterone receptor and human epidermal growth factor receptor 2 in four. EBUS-TBNA is an accurate procedure for the diagnosis of thoracic lymph node metastases in patients with extrathoracic malignancies and should be an initial diagnostic tool in these patients. Furthermore, EBUS-TBNA can obtain high-quality specimens from metastatic lymph nodes for use in molecular analyses.

Fig. 1

Distribution of patients by EBUS-TBNA findings, follow-up and final diagnosis

Fig. 2

a Cell block (haematoxylin–eosin 20×): mediastinal lymph node metastasis from colon adenocarcinoma. b At the immunohistochemical analysis, tumor cells were positive for keratin 20 (20×). Immunohistochemistry was consistent with metastasis from colon cancer

Fig. 3

a Cell block (haematoxylin–eosin 40×): mediastinal lymph node metastasis from medullary thyroid carcinoma. b At the immunohistochemical analysis, tumor cells were positive for calcitonin (40×). Immunohistochemistry was consistent with metastasis from medullary thryroid carcinoma