Improving diagnostic yield of pancreatic serous cystadenoma with cyst fluid ancillary testing, adjunct immunohistochemistry, and additional fine‐needle biopsy sampling

ABSTRACT Background Fine‐needle aspiration (FNA) diagnosis of pancreatic serous cystadenoma (SCA) remains challenging. This retrospective study aimed to evaluate the roles of cyst fluid ancillary testing and combined fine‐needle biopsy (FNB) in improving the diagnostic yield. Methods The authors retrospectively reviewed cytology cases that were histologically confirmed SCAs. Clinical features and FNA cyst fluid biochemical and molecular analysis results along FNB findings were reviewed. Results The study cohort included 31 cases from 13 male and 18 female patients with a mean age of 65. The original cytologic diagnoses were nondiagnostic (n = 6, 19%), negative for malignant cells/cyst contents (n = 7, 23%), atypical cells (n = 3, 10%), nonmucinous cyst (n = 11, 35%), and serous cystadenoma (n = 4, 13%). Cyst fluid carcinoembryonic antigen (CEA) analysis was performed in 17 cases, all of which showed a low CEA level (