Background: Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-guided FNAB) is highly sensitive and specific in cytologic diagnosis and clinical staging of malignant neoplasms of the gastrointestinal tract, pancreas, liver, and lymph nodes. However, no study has been performed to evaluate its accuracy, sensitivity, specificity, and the cytomorphologic features of suspected primary ampullary tumors.
Methods: All EUS-guided FNABs of suspected primary ampullary lesions at the University of California Irvine Medical Center (Orange, CA) from January 1998 to September 2004 were retrospectively retrieved. The number of passes necessary to arrive at a preliminary diagnosis during adequacy assessment was documented. The cytologic features were analyzed with endosonographic correlation. Follow-up information was also collected.
Results: Thirty-five patients were found, 17 men and 18 women. The mean age of the patients was 68.9 years (range, 34-87 yrs). Adenocarcinoma was diagnosed in 13 patients. Atypical cells were found in six patients, four of which were suspicious for adenocarcinoma and two of which were consistent with reactive atypia. Adenoma was diagnosed in two patients and carcinoid tumor in one. Thirteen patients had a diagnosis that was negative for malignant cells. The average number of aspiration passes was 2.4 (range, 1-6 passes). Follow-up information was available in 27 patients. There were three false-negative results and no false-positive results. The sensitivity, specificity, and the positive and the negative predictive values were 82.4%, 100%, 100%, and 76.9%, respectively. The diagnostic accuracy was 88.8%. The consistent cytologic features in specimens that were positive or suspicious for adenocarcinoma included high cellularity, single cells, 3-dimensional cell balls, high nuclear-to-cytoplasmic ratio, prominent nucleoli, coarse/uneven distribution of chromatin, and necrosis.
Conclusions: EUS-guided FNAB was accurate, sensitive, and specific in the assessment of suspected primary ampullary masses. Adenoma presented a diagnostic challenge and endosonographic correlation was instrumental to increase the diagnostic accuracy.