Background The incidence of occult metastatic disease (OMD) in pancreatic ductal adenocarcinoma (PDAC) and associated risk factors are largely unknown. Methods We identified all patients with PDAC, who had an aborted oncologic operation due to OMD within a 10‐year period. The cases were matched to a cohort of resected PDAC patients on a 1:3 ratio, based on age and sex, for comparison of preoperative clinical characteristics and potential risk factors for OMD. Results In the studied period, 117 patients with OMD were identified in 1423 pancreatectomies performed for PDAC (8%). Liver metastases were the most common finding (79%) followed by peritoneal implants (16%). When compared with non‐OMD cases, patients with OMD presented more often with abdominal pain (P < 0.001), and higher preoperative carbohydrate antigen 19‐9 (CA 19‐9) values ( P = 0.007). Additionally, indeterminate liver lesions on preoperative computed tomography (CT) were identified in 40% of OMD versus 17% of non‐OMD patients ( P < 0.001). Multivariable analysis distinguished four independent predictors for OMD: indeterminate lesions on preoperative CT, tumor size > 30 mm, abdominal pain, and preoperative CA 19‐9 > 192 U/mL. Conclusions Occurrence of OMD in PDAC accounts for 8% of cases. Preoperative CA 19‐9 > 192 U/mL, primary tumor size > 30 mm, and identification of indeterminate lesions in preoperative CT may indicate the need for diagnostic laparoscopy.

Differentiating LECs from premalignant pancreatic cystic neoplasms remains difficult. Findings of an exophytic growth pattern of the lesion on abdominal imaging and the presence of specific cytomorphologic features in the EUS-FNA biopsy could help clinicians diagnose LEC preoperatively.