EBUS-TBNA in the workup of a mediastinal mass.

Guided by endobronchial ultrasound (EBUS), mediastinal lymph nodes can be reached in a safe, minimally invasive manner, allowing fine needle aspiration for cytologic diagnosis with a high sensitivity and specificity. In describing the following clinical case, we demonstrate the use of EBUS-transbronchial needle aspiration (TBNA) in the workup of a paratracheal mass in a young female patient. Immunocytochemical analysis revealed it to be a peripheral nerve sheath tumor. EBUS-TBNA complemented computerized tomography, fluoro-deoxy-glucose positron emission tomography, and magnetic resonance imaging in establishing the diagnosis of this infrequently encountered mediastinal neoplasm. Fluoro-deoxy-glucose positron emission tomography has a potential to discriminate between high-grade sarcoma and benign soft tissue tumors, but it remains unreliable to differentiate benign schwannoma from low-grade sarcomas such as malignant peripheral nerve sheath tumor. When properly prepared, cell blocks obtained from TBNA of a paratracheal mass offer the possibility of cytologic examination and immunocytochemical staining, confirming the diagnosis of mediastinal neurogenic tumors.