Spectrum of gallbladder malignancies on fine-needle aspiration cytology: 5 years retrospective single institutional study with emphasis on uncommon variants

BackgroundUltrasound-guided fine-needle aspiration cytology (FNAC) is the standard modality for diagnosis of gallbladder malignant neoplasms. Adenocarcinoma is the most common malignancy; however, other types may also be encountered. The aim of this study was to perform a retrospective analysis of gallbladder malignancies diagnosed on FNAC in the last 5 years to document the cytomorphological spectrum and the variations thereof. MethodsThe records of the Department of Cytology, PGIMER were searched from July 2010 to June 2015 and all cases of gallbladder malignancies were analyzed in detail for cytomorphological characteristics. Giemsa and Hematoxylin-Eosin stained slides were evaluated with immunocytochemistry on cell blocks wherever available. ResultsA total of 791 gallbladder FNAC performed in cases of radiologically suspected gallbladder malignancies were evaluated. Gallbladder carcinoma (GBC) was more common in females with a male to female ratio of 1:2.3. Median age was 53.4 years (range 24-85 years); 81 cases (10.2%) were nondiagnostic and 31 (3.9%) were suspicious of malignancy. A total of 645 FNACs were positive for malignancy, out of which there were 619 (96%) adenocarcinoma and 26 cases with unusual malignancies. These included adenosquamous carcinoma (8, 1.2%), squamous cell carcinoma (7, 1.1%), small cell neuroendocrine carcinoma (9, 1.3%), and one case each of undifferentiated carcinoma and Non Hodgkin lymphoma respectively. The unusual malignancies were confirmed on cell block immunocytochemistry. ConclusionAdenocarcinoma is most common type of gallbladder malignancy; however, other unusual types of carcinomas occur and in such cases, FNAC supplemented by cell block immunocytochemistry is required for an accurate diagnosis. Diagn. Cytopathol. 2017;45:36-42. (c) 2016 Wiley Periodicals, Inc.