Endoscopic ultrasound-guided fine needle aspiration of pleural and ascitic fluid.

Endoscopic ultrasound (EUS) has been established as an important modality for staging gastrointestinal malignancies. We have previously described the new technique of EUS-guided fine needle aspiration (FNA) in diagnosing submucosal and extraluminal tumors and lymph nodes. We now report the novel application of EUS and EUS-guided FNA in diagnosing malignant ascites and malignant pleural effusion in two patients with gastric carcinoma. In the first patient, CT did not detect any effusion or ascites. EUS-guided FNA diagnosed cytologically that both fluids were malignant, thereby precluding surgery. The second patient had a small pleural effusion on CT that was not detected on the chest x-ray. EUS-guided FNA made the cytological diagnosis of recurrent adenocarcinoma in the pleural fluid. These two cases demonstrate for the first time that EUS combined with EUS-guided FNA can be used for the diagnosis of malignant pleural or ascitic fluid in patients with gastrointestinal malignancies and might further extend the staging capabilities of EUS.