Endoscopic ultrasonography-guided fine-needle cytodiagnosis of mediastinal metastases from renal cell cancer

Background: Endoscopic ultrasonography (EUS) has become the investigation of choice for the evaluation of the mediastinum. Lung and mediastinum are amongst the common sites of metastases from renal cell cancer (RCC). We diagnosed metastatic RCC in mediastinal lymph nodes by EUS-guided fine-needle aspiration (FNA) cytology. Methods: A total of 111 patients with mediastinal lymph nodes had undergone EUS-FNA using a linear array echo endoscope and a 170 cm, 22 G GIP needle consecutively. Smears were prepared, air-dried, and sent to an independent cytologist. Results: Seven patients (all males, mean age 64.8 years, range 45-72) were diagnosed cytologically to have metastatic RCC. Three patients had been diagnosed with RCC in the past (2, 7, and 17 years ago) while in the others, this was primarily diagnosed on the basis of EUS-FNA. The EUS features of these mediastinal RCC metastases include irregular lesions with inhomogenous echotexture, measuring 2.8 cm (median; range 1.0-4.5) located predominantly in the posterior mediastinum. Conclusion: EUS-FNA diagnosis of metastatic RCC is safe and feasible. It is especially useful in the evaluation of the mediastinum for suspected metastases. Cytology examination results in combination with clinical features could suggest the site of origin of the primary, assisting in further management.