[417] Prospective Analysis of Atypical Epithelial Cells as a High Risk Cytological Feature for Malignancy in Pancreatic Cysts

Martha B Pitman, Kurt A Yaeger, William R Brugge, Mari Mino-Kenudson. Massachusetts General Hospital, Boston, MA

Background: By retrospective analysis, we have reported on the significance of atypical epithelial cells (AEC) in mucinous cyst fluids for detecting at least moderate dysplasia and predicting high-grade dysplasia (HGD) or worse, including in small branch-duct intraductal papillary mucinous neoplasms (IPMN). Here we report on the outcome of the prospective application of reporting AEC or worse (≥AEC) in EUS-FNA specimens of pancreatic cysts.
Design: All EUS-FNA of pancreatic cysts performed between Jan. 2006 and June 2011 were evaluated. Cytological, histological, imaging and cyst fluid CEA data were recorded. Performance characteristics of ≥AEC on cytology for predicting malignancy or mucinous cysts with high grade dysplasia was assessed. Nondiagnostic FNAs were excluded (no epithelial cells +/- CEA<192 ng/ml). Cysts were classified as mucinous on cytology with CEA >192 ng/ml or mucinous epithelium +/- extracellular mucin. Endocrine neoplasms are classified as malignant. Original reports were used. Atypical epithelial cells were defined as epithelial cells singly or in clusters with increased N/C ratio, nuclear hyperchromasia +/- membrane abnormalities and +/- cytoplasmic vacuoles, and not recognizable as GI contamination.
Results: A total of 404 EUS-FNAs were performed in 352 patients. The 70 patients with histological confirmation of diagnosis were analyzed using the FNA just prior to resection in patients with multiple FNAs of the same site; 4 aspirates were non-diagnostic and not included in the performance calculations (Table 1).

Histologically Confirmed Cysts (n=66)

	Malignant	Not Malignant
	(TP; n=20)	(FP; n=6)
≥AEC on cytology	PDAC (7)	IPMN-MD (4)
	IPMN-inv (5); HGD (4)	MCN-denuded (1)
	Cystic PanNET (4)	Non-neoplastic MC (1)
	(FN; n=4)	(TN; n=36)
	PDAC (2)	Pseudocyst (17)
	IPMN-HGD (1)	Serous cystadenoma (1)
	Cystic PanNET (1)	IPMN-LGD (5); MD (6)
		MCN-LGD (4); MD (3)

Sensitivity=83%; Specificity=86%; PPV= 77%; NPV= 90%; Accuracy =85%
If moderate dysplasia is considered a true positive with AEC cytology, specificity increases to 97%, but at the expensive of sensitivity, 68%, and accuracy 80%.
Conclusions: Cytology is a specific and fairly accurate screening test for pancreatic cysts that require resection. AEC or worse on cytology predicts either a secondarily cystic solid neoplasm that requires resection, or a mucinous cyst with at least moderate dysplasia (specificity 97%), and suspicious for a mucinous cyst with HGD or worse (specificity 86%).
Category: Cytopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 61, Tuesday Morning