Background:
Recently, endoscopic ultrasound-guided fine-needle aspiration (eus-fna) has emerged as a diagnostic adjunct for small pancreatic lesions and abdominal and mediastinal lymph node diseases.
Design:
During a 21-month period, we performed 179 eus-fnas in 166 consecutive patients; these data are the subject of this study. an average of 2.6 needle passes were obtained and aspiration was performed most commonly in the pancreas (162 cases, 91%). the fna smears were reviewed using six diagnostic categories (negative for malignancy/nondiagnostic [nnd], atypia, suspicious for malignancy, benign tumor/cyst, neuroendocrine neoplasm [nen], and carcinoma). the review diagnosis was correlated with the histologic diagnosis made on resection or surgical biopsy specimens in 70 cases. up to 17 months of clinical follow-up were sought for the cases with a negative or inconclusive fna diagnosis and no diagnostic tissue confirmation (81 cases).
Results:
The review fna diagnoses were as follows: nnd (49 cases), atypia (17 cases), suspicious for malignancy (12 cases), benign tumor/cyst excluding nen (10 cases), nen (6 cases), carcinoma (85 cases). follow-up methods included resection (49 cases), surgical biopsy (21 cases), repeat fna or brushing cytology (28 cases), and clinical follow-up only (81 cases). of the 49 nnd cases, 23 (47%) had positive follow-up results (i.e., false-negative diagnosis) that were confirmed by tissue diagnosis (resection/surgical biopsy in 11 cases [48%] and repeat fna/brushing in 12 cases [52%]). these included pancreatic/ampullary adenocarcinoma in 20 cases, esophageal squamous carcinoma in 1 case, and nen in 2 cases. follow-up also revealed carcinoma in all 12 suspicious cases and 13 pancreatic adenocarcinomas and 1 microcystic adenoma in 14 of the 17 atypical cases. overall, repeat computed tomography (ct)-guided fna samples yielded a definite diagnosis in four atypical and seven nnd cases, whereas eus-fna results provided a definite diagnosis in three cases in which ct-guided fna failed and in two cases in which ampullary biopsy failed. no false-positive cases were identified. the false-negative rate due to inadequate sampling was 13.2%. sensitivity (including cases with inadequate cellularity and nondiagnostic aspirates) was 81.7% and specificity was 100%. none of the factors evaluated (lesion characteristics, aspiration site, and tumor type) significantly influenced diagnostic results.
Conclusion:
Eus-fna is a valuable diagnostic and staging tool with high specificity and sensitivity. negative or nondiagnostic cases on eus-fna require further diagnostic work for a definitive diagnosis when clinical or radiographic findings do not correlate with the fna results.