The role of cytopathology and cyst fluid analysis in the preoperative diagnosis and management of pancreatic cysts >3 cm.

BACKGROUND

Pancreatic cyst size >3 cm is a worrisome rather than high-risk feature for malignancy based on the 2012 International Guidelines for the management of mucinous cysts. The value of cytology in preoperative evaluation and surgical triage is unclear.

METHODS

All pancreatic cysts >3 cm resected over a 7-year period were evaluated for clinical, radiologic, and pathologic information. Performance of cytology for the detection of malignancy and surgical triage compared with imaging was assessed.

RESULTS

There were 93 histologically confirmed cysts, 52 of which were mucinous and 41 of which were nonmucinous. Of these, 37% were malignant, including 16 nonmucinous malignancies and 18 mucinous cysts (12 with invasive carcinoma, 6 with high-grade dysplasia). Thirty-nine cysts (41% malignant, 59% benign) were not subject to endoscopic ultrasound-fine needle aspiration (EUS-FNA) prior to resection (average size, 6.0 cm). Fifty-four were evaluated by EUS-FNA, with 35 available for review (average size, 5.4 cm). Cytology/cyst fluid analysis had the highest specificity (88.9%) compared with imaging, whereas magnetic resonance imaging (MRI) showed the highest sensitivity (100%). MRI had the highest predictive value for mucinous (100%) versus nonmucinous cysts (100%). MRI and EUS were able to predict malignancy from the presence of high-risk imaging features in all cases. Some benign cases also showed high-risk imaging features on MRI (28.6%), computed tomography (32.3%), and EUS (45.8%). Cytology correctly classified 5 of 6 benign cysts with high-risk imaging as benign.

CONCLUSIONS

Preoperative evaluation of pancreatic cysts >3 cm is warranted, as many are nonmucinous cysts and not high-grade. Cytology is more specific than imaging for the detection of malignancy in cysts >3 cm.