Background:
Expectant management of serous cystadenoma (sca) of the pancreas requires an accurate preoperative diagnosis. previously published cytologic diagnostic sensitivities have ranged widely, from 10% to 100%. in the current study, the authors evaluated the diagnostic sensitivity of endoscopic ultrasound (eus)-guided fine-needle aspiration biopsy (fnab) and cross-sectional imaging for sca.
Methods:
Group i consisted of 21 histologically confirmed scas. group ii (n = 7 lesions) lacked histologic confirmation and was defined by eus findings that were consistent with sca and a cyst fluid carcinoembryonic antigen (cea) level <5 ng/ml. group iii was comprised of 2 nonserous and potentially malignant cysts of the pancreas for which a preoperative diagnosis of sca was considered. cross-sectional imaging data were recorded. the smears were evaluated for the presence of serous lining epithelium, gastrointestinal-contaminating epithelium, and inflammatory cells including hemosiderin-laden macrophages. the authors also evaluated the presence of hemosiderin-laden macrophages in a series of 110 fna specimens from histologically confirmed neoplastic mucinous cysts of the pancreas and 45 pseudocysts of the pancreas.
Results:
Prospectively among group i lesions, the appearance on computed tomography (ct) was considered definitive for sca in 3 of 12 cases (25%). the histologically confirmed sca cases had cea levels of <5 ng/ml, except for 1 case for which the cea level was 176.5 ng/ml. a cytologic diagnosis of sca was made prospectively in only 1 ct-guided case. retrospectively, 3 intraoperative fnas and 1 additional ct-guided aspirate contained rare epithelial cells of a sca. none of the eus-guided aspirates demonstrated serous epithelium. among group ii aspiration specimens, only 1 contained serous epithelial cells. approximately 52% of the eus-guided aspirates demonstrated gastrointestinal contamination. this glandular epithelium was categorized as atypical in 2 cases. hemosiderin-laden macrophages were identified in 43% of the scas. conversely, only 2% of neoplastic mucinous cysts and 9% of pseudocysts produced hemosiderin-laden macrophages in aspirate fluid.
Conclusions:
In the current study, serous epithelial cells were identified in <20% of cases. gastrointestinal-contaminating epithelium, often observed in eus-guided aspirates, further contributes to difficulties in interpretation. the presence of hemosiderin-laden macrophages as a surrogate marker for sca requires further study. a preoperative diagnosis of sca remains a challenge, and an eus-guided fnab is unlikely to provide the high level of diagnostic accuracy necessary to permit a nonoperative approach.