Pancreatic cysts with borderline CEA: Report from a single center

Background & aims: Pancreatic mucinous neoplasms exhibit variable malignant potential. Cyst fluid carcinoembryonic antigen (CEA) levels have good accuracy to differentiate mucinous from nonmucinous cysts. We sought to evaluate our population with borderline cyst fluid CEA. Materials and Methods: Retrospective single center study. Patients who underwent EUS–FNA of a pancreatic cyst, with fluid CEA between 5–800 ng/mL were selected and classified as intermediate (5–199 ng/mL) or high (200–800 ng/mL). Mann-Whitney test and Spearman correlation were applied as appropriate. Results: Sixty-one patients with a mean age of 61.2±13.0 were selected. Results of cytology included: Mucinous (2); Non mucinous (22); Malignancy (3); non diagnostic (17). Median cyst fluid CEA was 67.0 (IQR 22.9–132.3). There was no correlation between cyst size and CEA. Thirteen patients had surgery (table 1). In those, CEA was higher in mucinous cystadenoma compared with IPMT (median 213.3 vs. 47.0; p 0.03). Follow-up was limited to 9 cases (n=5 with intermediate CEA; n=4 with high CEA), for a median of 187.0 days (IQR: 77.0–381.5). CT scans were available in 7/9 and revealed no enlargement of the cyst. There was 1 complication (puncture of the common bile duct). Discussion: FNA-cytology results were generally poor. If both cytology and pathology were available (n=9), the former provided the diagnosis in only 2 cases (pseudocyst; ductal adenocarcinoma). Among patients with intermediate CEA, surgery revealed 7 mucinous neoplasm (one IPMT had HGD) and 1 malignant cancer which reinforces the need for close surveillance if surgical resection is deferred. In general, IPMT tend to have a lower CEA compared with mucinous cystadenomas. Lastly, most lesions selected for follow-up were unchanged, but a larger study with longer follow-up is needed to confirm this finding. In summary, a cyst fluid CEA between 5–200 ng/ml does not exclude a mucinous neoplasm. Additional studies are needed to address the natural history and the role for serial imaging studies and CEA measurements.

CEA			>200	<200
N=61			12	49
Surgery	n=13		3	10
		IPMT	-	5
		Mucin cyst	3	2
		Adenocarc	-	1
		Pseudocyst	-	1
		serous cys	-	1