Ultrasound-guided fine needle aspiration cytology of gallbladder lesions: a study of 596 cases

Objective: Fine needle aspiration (FNA) is not a commonly performed procedure for gallbladder lesions for fear of causing biliary peritonitis; hence data on gallbladder cytology is scarce. The aims of the present study were to evaluate the diagnostic application of ultrasound-guided (US) FNA cytology in the pre-operative diagnosis of neoplastic as well as non-neoplastic lesions of the gallbladder and to review the cytomorphological spectrum of gallbladder lesions encountered along with various diagnostic difficulties that can arise during reporting. Methods: The study was carried out on 596 patients with gallbladder lesions in whom US-guided FNA was performed over a 5-year period. In 130 cases, simultaneous aspirations from other organs were done. The histological correlation was available in 32 cases. No major complications such as haemorrhage, peritonitis, etc. were encountered related to the procedure. Results: The majority were mass lesions whereas in 73 cases (12.2%) only focal or diffuse gallbladder wall thickening was present. Cytological examination of 596 cases revealed malignancy in 462 (77.6%), 26 (4.4%) suspicious of malignancy, 23 (3.8%) inflammatory lesion, 29 negative (4.8%) and 56 cases showed necrosis only or were inadequate for any definite opinion. The lesions diagnosed on FNA cytology included carcinoma (predominantly adenocarcinoma), xanthogranulomatous cholecystitis (XGC), acute suppurative inflammation and tuberculosis. Of 26 with adequate cytology, 24 were accurate with respect to malignant (including one suspicious FNA) versus benign: one false positive and one false negative both involved xanthogranulomatous change. Conclusion: The present study is the largest series evaluating the role of US-guided FNA in the diagnosis of gallbladder lesions. It is a safe, rapid, reliable, cost-effective and reasonably accurate method for diagnosing gallbladder lesions. FNA should always be attempted in cases with a mass lesion.