Serous cystadenoma of the pancreas: limitations and pitfalls of endoscopic ultrasound-guided fine-needle aspiration biopsy.
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.
Belsley
Nicole A
NA
Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Pitman
Martha B
MB
Lauwers
Gregory Y
GY
Brugge
William R
WR
Deshpande
Vikram
V
D002288:Adenocarcinoma, Mucinous / Q000000981:diagnostic imaging / Q000473:pathology*; D000368:Aged; D044963:Biopsy, Fine-Needle; D020420:Cyst Fluid / Q000378:metabolism; D018293:Cystadenoma, Serous / Q000000981:diagnostic imaging / Q000473:pathology*; D003937:Diagnosis, Differential; D004724:Endoscopy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D010181:Pancreatic Cyst / Q000000981:diagnostic imaging / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography