Endobronchial ultrasound-guided transbronchial needle biopsy for diagnosis of mediastinal lymphadenopathy in patients with extrathoracic malignancy

Abstract

Mediastinal lymphadenopathy associated with extrathoracic malignancy or a metastasis of unknown origin (MUO) requires pathological verification. Surgical exploration or endoscopic ultrasound-guided fine needle aspiration is limited to application. We investigated the effectiveness of endobronchial ultrasound-guided transbronchial needle biopsy (EBUS-TBNA) for evaluating mediastinal lymphadenopathy in patients with an extrathoracic malignancy. We retrospectively analyzed data from 59 patients who underwent EBUS-TBNA with a core biopsy because of a suspected mediastinal metastasis between September 2008 and August 2010. All patients had previously been diagnosed with an extrathoracic malignancy (n = 39, 66.1%) or a suspected MUO without a thoracic lesion (n = 20, 33.9%). A total of 88 lymph nodes was analyzed. EBUS-TBNA findings indicated malignancies in 34 patients (57.6%). The EBUS-TBNA sensitivity and specificity for the detection of mediastinal malignancy in patients with a previous extrathoracic malignancy were 96.3% and 100%, respectively. For MUO patients without a thoracic lesion, the sensitivity and specificity were 61.5% and 100%, respectively. The overall sensitivity and specificity were 81.0% and 100%, respectively (P = 0.053). EBUS-TBNA is a safe and effective modality for evaluating mediastinal lymphadenopathy in patients with a previous extrathoracic malignancy or a MUO without a thoracic lesion. The application of this diagnostic tool is likely to have significant clinical implications.

Keywords: EBUS; Extrathoracic Malignancy; MUO; Mediastinal Adenopathy; Metastatic Cancer of Unknown Primary Site.

Fig. 1

Histologic finding on EBUS-TBNA sample using tissue specific immunohistochemical stains. (A) Histologic findings breast cancer (H&E stain, × 100) with (a) positive ER stains (× 200), (B) hepatocelluar carcinoma (H&E stain, ×200) with (b) positive CK stain (×400), (C) malignant melanoma including brownish pigments (H&E stain, × 200) with (c) positive S100 stains (× 400), and (D) renal cell carcinoma cells (H&E stain, × 100) with (d) positive CD10 stains (× 200). EBUS-TBNA, endobronchial ultrasound-guided transbronchial needle aspiration.