Atypical cytologic diagnostic category in EUS-FNA of the pancreas: follow-up, outcomes, and predictive models

The objective of this study was to assess how atypical diagnostic category (ADC) is followed up, its outcomes, and the predictors that are associated with subsequent diagnosis of neoplasm/malignancy.

We reviewed pancreatic endoscopic ultrasound fine-needle aspiration (EUS-FNA) with ADC and compared the rate of detection of neoplasms after a repeat FNA, a biopsy/resection, or a clinical follow-up following ADC. Logistic regression was used to determine the factors associated with the diagnosis of a neoplastic or a malignant lesion following ADC. Predictive probability for each case was calculated on the basis of the significant predictors, and whether it improved diagnostic performance was assessed.

Of 3832 cases that received pancreatic EUS-FNAs, 187 (4.9%) were ADC. A total of 93 neoplasms (55%), including 61 carcinomas (36%), were detected after an atypical cytologic diagnosis. Similar rates of detecting neoplasms were observed after repeat FNA or biopsy/resection but higher than after clinical follow-up. The presence of a mass, history of alcohol use, and absence of a history of pancreatitis were significant predictors of a higher rate of diagnosis of neoplasm. Weight loss and bile flow obstruction were more likely to be associated with higher rates of carcinoma. Predictive probability demonstrated a wide range of risk and changed the ambiguous diagnosis to informative in 30% of cases.

ADC of pancreas is associated with a high risk of benign and malignant neoplasms regardless of the method of follow-up. The presences of a mass, alcohol use, and absence of a history of pancreatitis are significant predictors of a diagnosis of neoplasm, whereas weight loss and bile duct obstruction are significant predictors of ductal carcinoma following an ADC.