Endoscopic Ultrasound Fine-Needle Aspiration Diagnosis of Synchronous Primary Pancreatic Adenocarcinoma and Effects on Staging and Resectability.

Synchronous primary pancreatic adenocarcinoma, defined as the simultaneous presence of 2 or more newly identified and anatomically separate primary adenocarcinomas within the pancreas, is reported rarely. We compared endoscopic ultrasound (EUS) and computed tomography (CT) and magnetic resonance imaging (MRI) findings from patients with synchronous primary pancreatic adenocarcinoma and their effects on cancer staging and treatment. We performed a retrospective analysis of the EUS database at the Mayo Clinic, from September 2008 through May 2016, to collect EUS, CT, MRI, and clinical data from patients with synchronous primary pancreatic adenocarcinoma. EUS and separate fine-needle aspiration of both tumors detected synchronous primary pancreatic adenocarcinoma in 11 patients (70.9 ± 10.4 y; 64% men). Of the 22 cancers, CT (n = 9) and MRI (n = 2) detected 9 (41%) cancers; in only 2 patients did CT detect both cancers. EUS increased cancer stage for 7 of the 11 (64%) patients and changed the status from resectable to unresectable for 3 of the 9 (33%) patients, compared with CT or MRI. EUS findings altered the likely extent of surgical resection for 3 patients. Synchronous primary pancreatic adenocarcinoma is reported rarely and may be undetected by CT or MRI; this could account for the false presumption of early tumor recurrence, rather than actual residual second tumor, leading to incomplete resection.