Endoscopic ultrasound-guided paracentesis of ascitic fluid: a morphologic study with ultrasonographic correlation

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been widely used for the diagnosis of primary and metastatic gastrointestinal (GI) and non-GI malignancies. Few studies have been published to evaluate the accuracy and the cytologic features of EUS-guided paracentesis in the diagnosis and staging of malignant neoplasms.

All EUS-guided paracenteses of ascitic fluid performed at the University of California Irvine Medical Center (UCIMC) from January 2003 to February 2006 were retrospectively retrieved. Corresponding EUS findings, cytology and histology slides, and follow-up information were reviewed.

One hundred one (101) cases were found. Two smears were submitted in 11 cases because of the scanty amount of fluid aspirated. In the remaining cases, 5 mL or less of fluid were aspirated in 56 patients, and, of 9 who had prior computed tomography (CT), ascitic fluid was not seen in 6. The cytologic diagnoses were as follows: 17 were positive for adenocarcinoma, 1 positive for metastatic small-cell carcinoma of the lung, 1 positive for diffuse large-cell lymphoma, 3 suspicious for adenocarcinoma, 1 suspicious for plasmacytoma, 4 atypical epithelial cells, and 74 negative. Cell block was available in 80 cases and immunohistochemical stains were performed in 71 cases to confirm the diagnosis. Six patients had peritoneal biopsy. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were 80%, 100%, 100%, 95%, and 96%, respectively.

EUS-guided paracentesis is a valuable aid in the cytologic diagnosis of malignant ascites. It is particularly useful when no abnormality is identified by CT.