Risk of malignancy in pancreatic cysts with cytology of high‐grade epithelial atypia

BACKGROUND: The risk of malignancy is weighed against the attendant risks of surgery in the clinical management of pancreatic cysts. The latter are a group of histologically diverse and prognostically variable entities, and the risk of malignancy therein is primarily based on imaging characteristics-with or without high-grade atypia. Cytologic criteria for high-grade atypia in intraductal papillary mucinous neoplasms have recently been defined, and its recognition in all pancreatic cysts may help to guide management. METHODS: All patients who underwent endoscopic ultrasound-guided fine-needle aspiration for a pancreatic cyst at Massachusetts General Hospital from June 2015 to October 2016 were prospectively evaluated. Clinical data, radiographic impressions, biochemical analyses, and cytologic diagnoses of 118 pancreatic cyst fine-needle aspiration biopsy specimens from 106 patients were reviewed. Clinical and radiologic data were used as follow-up for 86 patients, and histology was obtained in 20 cases. Cysts were classified by imaging as high-risk, worrisome, or low-risk as defined by the 2012 Fukuoka consensus guidelines. Cytology was categorized as low-grade or high-grade. Malignant histology included mucinous cysts with high-grade dysplasia, invasive adenocarcinomas, and neuroendocrine tumors. The risk of malignancy (ROM) was determined by histological outcome. RESULTS: The presence of high-grade cytology (P < .01) was the only statistically significant predictor of malignancy and was 89% sensitive and 98% specific for malignancy. The positive predictive value (ie, ROM) of high-grade atypia on cytology was 80%. CONCLUSIONS: High-grade atypia is both sensitive and specific for identifying high-risk pancreatic cysts and is associated with a high risk of malignancy, and thus resection is warranted.