Endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of mediastinal metastases of clear cell renal cell carcinoma

Evaluation of mediastinal lymphadenopathy in patients with a previous diagnosis of renal cell carcinoma (RCC) is critical for the determination of further treatment. A minimally invasive method of cytology sampling of mediastinal lymph nodes using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a useful tool in diagnosis. Between January 2010 and April 2018, we performed 1744 EBUS-TBNA studies of mediastinal and hilar lymph nodes for a variety of clinical indications including mediastinal malignancy. Sixteen patients (93.7% males, mean age 59.1 years, range 44-81 years) were diagnosed by cytological and cell block study to have metastatic clear cell RCC. Twelve patients had been diagnosed with clear cell RCC in the past (mean 39 months, range 4-89 months) while in four, the tumor was primarily diagnosed in the staging phase on the basis of EBUS-TBNA. The EBUS features of the mediastinal nodal masses included increase of size (mean 2.5 cm, range 1.6-3.8 cm), irregular, inhomogeneous, hypervascular, and hyperechoic echotexture. EBUS-TBNA is a procedure safe and effective for evaluating mediastinal lymphadenopathy in patients with clear cell RCC. Immunohistochemistry in the cell block is decisive for proper diagnosis. The cytologist plays a key role in the diagnosis of metastatic clear cell RCC due to the treatment implications that this neoplasm encompasses.